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Rütter D, van Gastel M, Leutzsch M, Nöthling N, SantaLucia D, Neese F, Fürstner A. Molybdenum(VI) Nitrido Complexes with Tripodal Silanolate Ligands. Structure and Electronic Character of an Unsymmetrical Dimolybdenum μ-Nitrido Complex Formed by Incomplete Nitrogen Atom Transfer. Inorg Chem 2024; 63:8376-8389. [PMID: 38663089 PMCID: PMC11080062 DOI: 10.1021/acs.inorgchem.4c00762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 04/05/2024] [Accepted: 04/11/2024] [Indexed: 05/07/2024]
Abstract
In contrast to a tungsten nitrido complex endowed with a tripodal silanolate ligand framework, which was reported in the literature to be a dimeric species with a metallacyclic core, the corresponding molybdenum nitrides 3 are monomeric entities comprising a regular terminal nitride unit, as proven by single-crystal X-ray diffraction (SC-XRD). Their electronic character is largely determined by the constraints imposed on the metal center by the podand ligand architecture. 95Mo nuclear magnetic resonance (NMR) and, to a lesser extent, 14N NMR spectroscopy allow these effects to be studied, which become particularly apparent upon comparison with the spectral data of related molybdenum nitrides comprising unrestrained silanolate, alkoxide, or amide ligands. Attempted nitrogen atom transfer from these novel terminal nitrides to [(tBuArN)3Mo] (Ar = 3,5-dimethylphenyl) as the potential acceptor stopped at the stage of unsymmetric dimolybdenum μ-nitrido complex 13a as the first intermediate along the reaction pathway. SC-XRD, NMR, electron paramagnetic resonance, and ultraviolet-visible spectroscopy as well as magnetometry in combination with density functional theory allowed a clear picture of the geometric and electronic structure of this mixed-valent species to be drawn. 13a is formally best described as an adduct of the type [(Mo[O])+III-(μN)-III-(Mo[N])+VI], S = 1/2 complex with (Mo[O])+III in the low-spin configuration, whereas related complexes such as [(AdS)3Mo-(μN)-Mo(NtBuAr)3] (19; Ad = 1-adamantyl) have previously been regarded in the literature as mixed-valent Mo+IV/Mo+V species. The spin population at the two Mo centers is uneven and notably larger at the more reduced Mo[O] atom, whereas the only spin present at the (μN) bridge is derived from spin polarization.
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Affiliation(s)
- Daniel Rütter
- Max-Planck-Institut
für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | | | - Markus Leutzsch
- Max-Planck-Institut
für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Nils Nöthling
- Max-Planck-Institut
für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Daniel SantaLucia
- Max-Planck-Institut
für Chemische Energiekonversion, 45470 Mülheim/Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut
für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut
für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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2
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Martínez JP, Trzaskowski B. An Anthracene-Thiolate-Ligated Ruthenium Complex: Computational Insights into Z-Stereoselective Cross Metathesis. J Phys Chem A 2023; 127:9465-9472. [PMID: 37916964 PMCID: PMC10658622 DOI: 10.1021/acs.jpca.3c05021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 09/26/2023] [Accepted: 09/29/2023] [Indexed: 11/03/2023]
Abstract
Stereoselective control of the cross metathesis of olefins is a crucial aspect of synthetic procedures. In this study, we utilized density functional theory methods to calculate thermodynamic and kinetic descriptors to explore the stereoselectivity of cross metathesis between allylbenzene and 2-butene-1,4-diyl diacetate. A ruthenium-based complex, characterized primarily by an anthracene-9-thiolate ligand, was designed in silico to completely restrict the E conformation of olefins through a bottom-bound mechanism. Our investigation of the kinetics of all feasible propagation routes demonstrated that Z-stereoisomers of metathesis products can be synthesized with an energy cost of only 13 kcal/mol. As a result, we encourage further research into the synthetic strategies outlined in this work.
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Affiliation(s)
- Juan Pablo Martínez
- Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warszawa, Poland
| | - Bartosz Trzaskowski
- Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warszawa, Poland
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3
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Zhao Z, Lin H, Zhang Z, Gao X, Ji C, Zhou J, Zhou F. A Highly Stereoselective Redox Isomerization-Reductive Deuteration Sequence of Propargyl Amines to α-Deuterated Amino Acids. Org Lett 2023; 25:7895-7899. [PMID: 37874766 DOI: 10.1021/acs.orglett.3c03140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
Herein, we report a Cu-catalyzed redox isomerization-reductive deuteration sequence, providing facile access to a range of α-deuterated amino acid esters featuring an Z-configured alkene moiety with high yields. The advantages of this sequence include mild conditions, broad substrate scope, and excellent stereoselectivity. This research also represents a rare example of the Z-selective redox isomerization of propargyl amines.
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Affiliation(s)
- Zhipeng Zhao
- State Key Laboratory of Molecular & Process Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Process and Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, East China Normal University, 3663 N Zhongshan Road, Shanghai 200062, China
| | - Hongrui Lin
- State Key Laboratory of Molecular & Process Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Process and Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, East China Normal University, 3663 N Zhongshan Road, Shanghai 200062, China
| | - Zheng Zhang
- State Key Laboratory of Molecular & Process Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Process and Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, East China Normal University, 3663 N Zhongshan Road, Shanghai 200062, China
| | - Xiaotong Gao
- School of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331, China
| | - Congbin Ji
- School of Chemistry and Environmental Sciences, Shangrao Normal University, Shangrao 334001, China
| | - Jian Zhou
- State Key Laboratory of Molecular & Process Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Process and Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, East China Normal University, 3663 N Zhongshan Road, Shanghai 200062, China
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Shanghai 200032, China
| | - Feng Zhou
- State Key Laboratory of Molecular & Process Engineering, Shanghai Key Laboratory of Green Chemistry and Chemical Process and Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, East China Normal University, 3663 N Zhongshan Road, Shanghai 200062, China
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4
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Li S, Feng S, Zhou Y, Liu C, Chen B, Xing X. Development of Highly Enantio- and Z-Selective Grubbs Catalysts via Controllable C-H Bond Activation. J Am Chem Soc 2023; 145:22745-22752. [PMID: 37800981 DOI: 10.1021/jacs.3c08420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
Asymmetric olefin metathesis is a powerful strategy for stereocontrolled synthesis that allows the formation of chiral elements in conjunction with carbon-carbon double bonds. Here, we report a new series of cyclometalated stereogenic-at-Ru catalysts that enable highly efficient asymmetric ring opening/cross-metathesis (AROCM) and asymmetric ring-closing metathesis (ARCM) reactions. Single enantiomers of these catalysts with either right-handed or left-handed configurations at the Ru center can be easily accessed via highly stereoselective C-H bond activation-based cyclometalation. Right-handed chiral Ru catalysts enabled the Z- and enantioselective AROCM of a wide range of norbornenes and terminal alkenes, generating densely functionalized cyclopentanes with excellent stereo- and enantioselectivities (99:1 Z/E, up to 99% ee). Left-handed chiral Ru catalysts enabled the facile ARCM of sterically unhindered, all-terminal prochiral trienes, which had not been achieved by previous Ru catalysts, providing simple cyclic ethers and amides with tertiary or quaternary carbon stereocenters with excellent enantioselectivities (up to 99% ee).
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Affiliation(s)
- Shaofeng Li
- Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China
| | - Shijie Feng
- Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yali Zhou
- Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China
| | - Chao Liu
- Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China
| | - Bo Chen
- Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xiangyou Xing
- Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China
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5
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Qin C, Koengeter T, Zhao F, Mu Y, Liu F, Houk KN, Hoveyda AH. Z-Trisubstituted α,β-Unsaturated Esters and Acid Fluorides through Stereocontrolled Catalytic Cross-Metathesis. J Am Chem Soc 2023; 145:3748-3762. [PMID: 36720176 PMCID: PMC10075318 DOI: 10.1021/jacs.2c13245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Catalytic cross-metathesis (CM) reactions that can generate trisubstituted alkenes in high stereoisomeric purity are important but remain limited in scope. Here, CM reactions are introduced that generate Z-trisubstituted α-methyl, α,β-unsaturated, alkyl and aryl esters, thiol esters, and acid fluorides. Transformations are promoted by a Mo bis-aryloxide, a monoaryloxide pyrrolide, or a monoaryloxide chloride complex; air-stable and commercially available paraffin tablets containing a Mo complex may also be used. Alkyl, aryl, and silyl carboxylic esters as well as thiol esters and acid fluoride reagents are either purchasable or can be prepared in one step. Products were obtained in 55-95% yield and in 88:12->98:2 Z/E ratio (typically >95:5). The applicability of the approach is highlighted by a two-step conversion of citronellol to an isomintlactone precursor (1.7 g, 73% yield, and 97:3 Z/E) and a single-step transformation of lanosterol acetate to 3-epi-anwuweizic acid (72% yield and 94:6 Z/E). Included are the outcomes of DFT studies, regarding several initially puzzling catalyst activity trends, providing the following information: (1) it is key that a disubstituted Mo alkylidene, generated by a competing homo-metathesis (HM) pathway, can re-enter the productive CM cycle. (2) Whereas in a CM cycle the formation of a molybdacyclobutane is likely turnover-limiting, the collapse of related metallacycles in a HM cycle is probably rate-determining. It is therefore the relative energy barrier required for these steps that determines whether CM or HM is dominant with a particular complex.
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Affiliation(s)
- Can Qin
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA
- Supramolecular Science and Engineering Institute, University of Strasbourg, CNRS, 67000 Strasbourg, France
| | - Tobias Koengeter
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - Fengyue Zhao
- College of Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yucheng Mu
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - Fang Liu
- College of Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - K. N. Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
| | - Amir H. Hoveyda
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA
- Supramolecular Science and Engineering Institute, University of Strasbourg, CNRS, 67000 Strasbourg, France
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6
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On the stereoselectivity of the cross metathesis of olefins catalyzed by a second-generation catalyst. CATAL COMMUN 2022. [DOI: 10.1016/j.catcom.2022.106552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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7
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Sieg G, Müller I, Weißer K, Werncke CG. Taming the stilbene radical anion. Chem Sci 2022; 13:13872-13878. [PMID: 36544743 PMCID: PMC9710230 DOI: 10.1039/d2sc04451j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 11/08/2022] [Indexed: 11/11/2022] Open
Abstract
Radical anions appear as intermediates in a variety of organic reductions and have recently garnered interest for their role as mediators for electron-driven catalysis as well as for organic electron conductor materials. Due to their unstable nature, the isolation of such organic radical anions is usually only possible by using extended aromatic systems, whereas non-aromatic unsaturated hydrocarbons have so far only been observed in situ. We herein report the first isolation, structure and spectroscopic characterization of a simple aryl substituted alkene radical anion, namely that of stilbene (1,2-diphenyl ethylene), achieved by encapsulation between two [K{18c6}] cations. The formation of the radical anion is accompanied by Z → E isomerization of the involved double bond, also on a catalytic scale. Employing the linear iron(i) complex [Fe(NR2)2]- as a reductant and coordination site also allows for this transformation, via formation of an iron(ii) bound radical anion. The use of the iron complex now also allows for Z → E isomerization of electron richer, simple alkenes bearing either mixed alkyl/aryl or even bis(alkyl) substitution.
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Affiliation(s)
- Grégoire Sieg
- Fachbereich Chemie, Philipps-Universität MarburgHans-Meerwein-Straße 435037 MarburgGermany
| | - Igor Müller
- Fachbereich Chemie, Philipps-Universität MarburgHans-Meerwein-Straße 435037 MarburgGermany
| | - Kilian Weißer
- Institut für Chemie, Humboldt-Universität zu BerlinBrook-Taylor-Str. 212489 BerlinGermany
| | - C. Gunnar Werncke
- Fachbereich Chemie, Philipps-Universität MarburgHans-Meerwein-Straße 435037 MarburgGermany
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8
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Buchowicz W, Guńka PA, Buchalski P, Piszcz M, Buś S, Mrozowicz M, Mazur M, Wasilewski R. E/ Z Switchable Ring-Closing Metathesis in 1,1′-Bis(but-3-enyl)ferrocenes: Synthesis and Characterization of Axially Chiral ansa[6]-Ferrocenes. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Włodzimierz Buchowicz
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664, Poland
| | - Piotr A. Guńka
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664, Poland
| | - Piotr Buchalski
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664, Poland
| | - Michał Piszcz
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664, Poland
| | - Sylwia Buś
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664, Poland
| | - Michał Mrozowicz
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664, Poland
| | - Maria Mazur
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664, Poland
| | - Rafał Wasilewski
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664, Poland
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9
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Hu C, Wang XF, Wei R, Hu C, Ruiz DA, Chang XY, Liu LL. Crystalline monometal-substituted free carbenes. Chem 2022. [DOI: 10.1016/j.chempr.2022.06.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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Mizukami D, Iio K, Oda M, Onodera Y, Fuwa H. Tandem Macrolactone Synthesis: Total Synthesis of (-)-Exiguolide by a Macrocyclization/Transannular Pyran Cyclization Strategy. Angew Chem Int Ed Engl 2022; 61:e202202549. [PMID: 35243740 DOI: 10.1002/anie.202202549] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Indexed: 12/25/2022]
Abstract
Tetrahydropyran-containing macrolactones were synthesized by integrating Meyer-Schuster rearrangement, macrocyclic ring-closing metathesis, and transannular oxa-Michael addition under gold and ruthenium catalysis. Single-step access to a variety of 14- to 20-membered macrolactones containing a tetrahydropyran ring was possible from readily available linear precursors in good yields and with moderate to excellent diastereoselectivity. A 13-step synthesis of (-)-exiguolide, an anticancer marine macrolide, showcased the feasibility of our tandem reaction sequence for macrolactone synthesis and also demonstrated the power of transannular reactions for rapid assembly of the tetrahydropyran rings of the target natural product.
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Affiliation(s)
- Daichi Mizukami
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
| | - Kei Iio
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
| | - Mami Oda
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
| | - Yu Onodera
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 981-8577, Japan
| | - Haruhiko Fuwa
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
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11
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E- and Z-trisubstituted macrocyclic alkenes for natural product synthesis and skeletal editing. Nat Chem 2022; 14:640-649. [PMID: 35577918 DOI: 10.1038/s41557-022-00935-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 03/24/2022] [Indexed: 12/24/2022]
Abstract
Many therapeutic agents are macrocyclic trisubstituted alkenes but preparation of these structures is typically inefficient and non-selective. A possible solution would entail catalytic macrocyclic ring-closing metathesis, but these transformations require high catalyst loading, conformationally rigid precursors and are often low yielding and/or non-stereoselective. Here we introduce a ring-closing metathesis strategy for synthesis of trisubstituted macrocyclic olefins in either stereoisomeric form, regardless of the level of entropic assistance. The goal was achieved by addressing several unexpected difficulties, including complications arising from pre-ring-closing metathesis alkene isomerization. The power of the method is highlighted by two examples. The first is the near-complete reversal of substrate-controlled selectivity in the formation of a macrolactam related to an antifungal natural product. The other is a late-stage stereoselective generation of an E-trisubstituted alkene in a 24-membered ring, en route to the cytotoxic natural product dolabelide C.
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12
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Mizukami D, Iio K, Oda M, Onodera Y, Fuwa H. Tandem Macrolactone Synthesis: Total Synthesis of (−)‐Exiguolide by a Macrocyclization/Transannular Pyran Cyclization Strategy. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202202549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Daichi Mizukami
- Chuo University - Korakuen Campus: Chuo Daigaku - Korakuen Campus Department of Applied Chemistry JAPAN
| | - Kei Iio
- Chuo University - Korakuen Campus: Chuo Daigaku - Korakuen Campus Department of Applied Chemistry JAPAN
| | - Mami Oda
- Chuo University - Korakuen Campus: Chuo Daigaku - Korakuen Campus Department of Applied Chemistry JAPAN
| | - Yu Onodera
- Tohoku University - Katahira Campus: Tohoku Daigaku Graduate School of Life Sciences JAPAN
| | - Haruhiko Fuwa
- Chuo University Department of Applied Chemistry 1-13-27 KasugaBunkyo-ku 112-8551 Tokyo JAPAN
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13
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Martínez JP, Trzaskowski B. Olefin Metathesis Catalyzed by a Hoveyda-Grubbs-like Complex Chelated to Bis(2-mercaptoimidazolyl) Methane: A Predictive DFT Study. J Phys Chem A 2022; 126:720-732. [PMID: 35080885 PMCID: PMC8842278 DOI: 10.1021/acs.jpca.1c09336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Although highly selective
complexes for the cross-metathesis of
olefins, particularly oriented toward the productive metathesis of Z-olefins, have been reported in recent years, there is
a constant need to design and prepare new and improved catalysts for
this challenging reaction. In this work, guided by density functional
theory (DFT) calculations, the performance of a Ru-based catalyst
chelated to a sulfurated pincer in the olefin metathesis was computationally
assessed. The catalyst was designed based on the Hoveyda–Grubbs
catalyst (SIMes)Cl2Ru(=CH–o–OiPrC6H4) through the substitution
of chlorides with the chelator bis(2-mercaptoimidazolyl)methane. The
obtained thermodynamic and kinetic data of the initiation phase through
side- and bottom-bound mechanisms suggest that this system is a versatile
catalyst for olefin metathesis, as DFT predicts the highest energy
barrier of the catalytic cycle of ca. 20 kcal/mol, which is comparable
to those corresponding to the Hoveyda–Grubbs-type catalysts.
Moreover, in terms of the stereoselectivity evaluated through the
propagation phase in the metathesis of propene–propene to 2-butene,
our study reveals that the Z isomer can be formed
under a kinetic control. We believe that this is an interesting outcome
in the context of future exploration of Ru-based catalysts with sulfurated
chelates in the search for high stereoselectivity in selected reactions.
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Affiliation(s)
- J Pablo Martínez
- Centre of New Technologies, University of Warsaw, 02-097 Warszawa, Poland
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14
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Liu Z, Sun S, Lou J. PhIO-Mediated Oxidative C═C Bond Cleavage and Reassembly toward Highly Functionalized Oxazolones. Org Lett 2022; 24:1323-1328. [PMID: 35129353 DOI: 10.1021/acs.orglett.1c04326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
An efficient PhIO-mediated oxidative C═C bond cleavage and reassembly of enaminone toward oxazolone with high regioselectivity has been reported. DFT calculations revealed that the reaction proceeded through an oxygen atom transfer, C═C bond cleavage, alkylthio migration, and reassembly cascade. This strategy is highlighted by high atom and step economy with formation of five bonds in one pot and generation of a high-valued oxazolone skeleton under mild conditions.
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Affiliation(s)
- Zhuqing Liu
- Advanced Research Institute for Multidisciplinary Science, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China.,State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China
| | - Shaobin Sun
- Advanced Research Institute for Multidisciplinary Science, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China
| | - Jiang Lou
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China.,State Key Laboratory of Pulp and Paper Science & Technology of Ministry of Education, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China
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15
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Alassad N, Nechmad NB, Phatake RS, Reany O, Lemcoff NG. Steric and electronic effects in latent S-chelated olefin metathesis catalysts. Catal Sci Technol 2022. [DOI: 10.1039/d2cy00943a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work, the structure, latency, and activity of twelve sulfur-chelated ruthenium precatalysts were studied by systematically varying their ligand shell.
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Affiliation(s)
- Nebal Alassad
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Noy B. Nechmad
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Ravindra S. Phatake
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
- Department of Natural Sciences, The Open University of Israel, Ra'anana 4353701, Israel
| | - Ofer Reany
- Department of Natural Sciences, The Open University of Israel, Ra'anana 4353701, Israel
| | - N. Gabriel Lemcoff
- Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
- Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
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16
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Chen H, Shi Z, Hsu TG, Wang J. Overcoming the Low Driving Force in Forming Depolymerizable Polymers through Monomer Isomerization. Angew Chem Int Ed Engl 2021; 60:25493-25498. [PMID: 34499390 DOI: 10.1002/anie.202111181] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/03/2021] [Indexed: 11/09/2022]
Abstract
While depolymerizable polymers have been intensely pursued as a potential solution to address the challenges in polymer sustainability, most depolymerization systems are characterized by a low driving force in polymerization, which poses difficulties for accessing diverse functionalities and architectures of polymers. Here, we address this challenge by using a cyclooctene-based depolymerization system, in which the cis-to-trans alkene isomerization significantly increases the ring strain energy to enable living ring-opening metathesis polymerization at monomer concentrations ≥0.025 M. An additional trans-cyclobutane fused at the 5,6-position of the cyclooctene reduces the ring strain energy of cyclooctene, enabling the corresponding polymers to depolymerize into the cis-cyclooctene monomers. The use of excess triphenylphosphine was found to be essential to suppress secondary metathesis and depolymerization. The high-driving-force living polymerization of the trans-cyclobutane fused trans-cyclooctene system holds promise for developing chemically recyclable polymers of a wide variety of polymer architectures.
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Affiliation(s)
- Hanlin Chen
- School of Polymer Science and Polymer Engineering, University of Akron, 170 University Ave., Akron, OH, 44325, USA
| | - Zhen Shi
- School of Polymer Science and Polymer Engineering, University of Akron, 170 University Ave., Akron, OH, 44325, USA
| | - Tze-Gang Hsu
- School of Polymer Science and Polymer Engineering, University of Akron, 170 University Ave., Akron, OH, 44325, USA
| | - Junpeng Wang
- School of Polymer Science and Polymer Engineering, University of Akron, 170 University Ave., Akron, OH, 44325, USA
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17
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Chen H, Shi Z, Hsu T, Wang J. Overcoming the Low Driving Force in Forming Depolymerizable Polymers through Monomer Isomerization. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202111181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Hanlin Chen
- School of Polymer Science and Polymer Engineering University of Akron 170 University Ave. Akron OH 44325 USA
| | - Zhen Shi
- School of Polymer Science and Polymer Engineering University of Akron 170 University Ave. Akron OH 44325 USA
| | - Tze‐Gang Hsu
- School of Polymer Science and Polymer Engineering University of Akron 170 University Ave. Akron OH 44325 USA
| | - Junpeng Wang
- School of Polymer Science and Polymer Engineering University of Akron 170 University Ave. Akron OH 44325 USA
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18
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Hillenbrand J, Korber JN, Leutzsch M, Nöthling N, Fürstner A. Canopy Catalysts for Alkyne Metathesis: Investigations into a Bimolecular Decomposition Pathway and the Stability of the Podand Cap. Chemistry 2021; 27:14025-14033. [PMID: 34293239 PMCID: PMC8518412 DOI: 10.1002/chem.202102080] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Indexed: 11/28/2022]
Abstract
Molybdenum alkylidyne complexes with a trisilanolate podand ligand framework ("canopy catalysts") are the arguably most selective catalysts for alkyne metathesis known to date. Among them, complex 1 a endowed with a fence of lateral methyl substituents on the silicon linkers is the most reactive, although fairly high loadings are required in certain applications. It is now shown that this catalyst decomposes readily via a bimolecular pathway that engages the Mo≡CR entities in a stoichiometric triple-bond metathesis event to furnish RC≡CR and the corresponding dinuclear complex, 8, with a Mo≡Mo core. In addition to the regular analytical techniques, 95 Mo NMR was used to confirm this unusual outcome. This rapid degradation mechanism is largely avoided by increasing the size of the peripheral substituents on silicon, without unduly compromising the activity of the resulting complexes. When chemically challenged, however, canopy catalysts can open the apparently somewhat strained tripodal ligand cages; this reorganization leads to the formation of cyclo-tetrameric arrays composed of four metal alkylidyne units linked together via one silanol arm of the ligand backbone. The analogous tungsten alkylidyne complex 6, endowed with a tripodal tris-alkoxide (rather than siloxide) ligand framework, is even more susceptible to such a controlled and reversible cyclo-oligomerization. The structures of the resulting giant macrocyclic ensembles were established by single-crystal X-ray diffraction.
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Affiliation(s)
- Julius Hillenbrand
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - J. Nepomuk Korber
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - Nils Nöthling
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
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19
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Abstract
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For numerous enabling features and strategic virtues, contemporary
alkyne metathesis is increasingly recognized as a formidable synthetic
tool. Central to this development was the remarkable evolution of
the catalysts during the past decades. Molybdenum alkylidynes carrying
(tripodal) silanolate ligands currently set the standards; their functional
group compatibility is exceptional, even though they comprise an early
transition metal in its highest oxidation state. Their performance
is manifested in case studies in the realm of dynamic covalent chemistry,
advanced applications to solid-phase synthesis, a revival of transannular
reactions, and the assembly of complex target molecules at sites,
which one may not intuitively trace back to an acetylenic ancestor.
In parallel with these innovations in material science and organic
synthesis, new insights into the mode of action of the most advanced
catalysts were gained by computational means and the use of unconventional
analytical tools such as 95Mo and 183W NMR spectroscopy.
The remaining shortcomings, gaps, and desiderata in the field are
also critically assessed.
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Affiliation(s)
- Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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20
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Li WH, Yang J, Jing H, Zhang J, Wang Y, Li J, Zhao J, Wang D, Li Y. Creating High Regioselectivity by Electronic Metal-Support Interaction of a Single-Atomic-Site Catalyst. J Am Chem Soc 2021; 143:15453-15461. [PMID: 34506145 DOI: 10.1021/jacs.1c08088] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Ligands are the most commonly used means to control the regioselectivity of organic reactions. It is very important to develop new regioselective control methods for organic synthesis. In this study, we designed and synthesized a single-atomic-site catalyst (SAC), namely, Cu1-TiC, with strong electronic metal-support interaction (EMSI) effects by studying various reaction mechanisms. π cloud back-donation to the alkyne on the metal catalytic intermediate was enhanced during the reaction by using transient electron-rich characteristics. In this way, the reaction achieved highly linear-E-type regioselective conversion of electronically unbiased alkynes and completely avoided the formation of branched isomers (ln:br >100:1, TON up to 612, 3 times higher than previously recorded). The structural elements of the SACs were designed following the requirements of the synthesis mechanism. Every element in the catalyst played an important role in the synthesis mechanism. This demonstrated that the EMSI, which is normally thought to be responsible for the improvement in catalytic efficiency and durability in heterogeneous catalysis, now first shows exciting potential for regulating the regioselectivity in homogeneous catalysis.
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Affiliation(s)
- Wen-Hao Li
- Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Jiarui Yang
- Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Hongyu Jing
- Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Jian Zhang
- Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Yu Wang
- Shanghai Synchrotron Radiation Facilities, Shanghai Institute of Applied Physics, Chinese Academy of Science, Shanghai, 201204, China
| | - Jiong Li
- Shanghai Synchrotron Radiation Facilities, Shanghai Institute of Applied Physics, Chinese Academy of Science, Shanghai, 201204, China
| | - Jie Zhao
- School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Dingsheng Wang
- Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Yadong Li
- Department of Chemistry, Tsinghua University, Beijing, 100084, China
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21
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Meng Z, Spohr SM, Tobegen S, Farès C, Fürstner A. A Unified Approach to Polycyclic Alkaloids of the Ingenamine Estate: Total Syntheses of Keramaphidin B, Ingenamine, and Nominal Njaoamine I. J Am Chem Soc 2021; 143:14402-14414. [PMID: 34448391 PMCID: PMC8431342 DOI: 10.1021/jacs.1c07955] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Many
polycyclic marine
alkaloids are thought to derive from partly
reduced macrocyclic alkylpyridine derivatives via a transannular Diels–Alder
reaction that forms their common etheno-bridged diaza-decaline core
(“Baldwin–Whitehead hypothesis”). Rather than
trying to emulate this biosynthesis pathway, a route to these natural
products following purely chemical logic was pursued. Specifically,
a Michael/Michael addition cascade provided rapid access to this conspicuous
tricyclic scaffold and allowed different handles to be introduced
at the bridgehead quarternary center. This flexibility opened opportunities
for the formation of the enveloping medium-sized and macrocyclic rings.
Ring closing alkyne metathesis (RCAM) proved most reliable and became
a recurrent theme en route to keramaphidin B, ingenamine, xestocyclamine
A, and nominal njaoamine I (the structure of which had to be corrected
in the aftermath of the synthesis). Best results were obtained with
molybdenum alkylidyne catalysts endowed with (tripodal) silanolate
ligands, which proved fully operative in the presence of tertiary
amines, quinoline, and other Lewis basic sites. RCAM was successfully
interlinked with macrolactamization, an intricate hydroboration/protonation/alkyl-Suzuki
coupling sequence, or ring closing olefin metathesis (RCM) for the
closure of the second lateral ring; the use of RCM for the formation
of an 11-membered cycle is particularly noteworthy. Equally rare are
RCM reactions that leave a pre-existing triple bond untouched, as
the standard ruthenium catalysts are usually indiscriminative vis-à-vis
the different π-bonds. Of arguably highest significance, however,
is the use of two consecutive or even concurrent RCAM reactions en
route to nominal njaoamine I as the arguably most complex of the chosen
targets.
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Affiliation(s)
- Zhanchao Meng
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Simon M Spohr
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Sandra Tobegen
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Christophe Farès
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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22
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23
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Podewitz M, Sen S, Buchmeiser MR. On the Origin of E-Selectivity in the Ring-Opening Metathesis Polymerization with Molybdenum Imido Alkylidene N-Heterocyclic Carbene Complexes. Organometallics 2021; 40:2478-2488. [PMID: 34393318 PMCID: PMC8356225 DOI: 10.1021/acs.organomet.1c00229] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Indexed: 11/28/2022]
Abstract
The understanding and control of stereoselectivity is a central aspect in ring-opening metathesis polymerization (ROMP). Herein, we report detailed quantum chemical studies on the reaction mechanism of E-selective ROMP of norborn-2-ene (NBE) with Mo(N-2,6-Me2-C6H3)(CHCMe3)(IMes)(OTf)2 (1, IMes = 1,3-dimesitylimidazol-2-ylidene) as a first step to stereoselective polymerization. Four different reaction pathways based on an ene syn or ene anti approach of NBE to either the syn- or anti-isomer of the neutral precatalyst have been studied. In contrast to the recently established associative mechanism with a terminal alkene, where a neutral olefin adduct is formed, NBE reacts directly with the catalyst via [2 + 2] cycloaddition to form molybdacyclobutane with a reaction barrier about 30 kJ mol-1 lower in free energy than via the formation of a catalyst-monomer adduct. However, the direct cycloaddition of NBE was only found for one out of four stereoisomers. Our findings strongly suggest that this stereoselective approach is responsible for E-selectivity and point toward a substrate-specific reaction mechanism in olefin metathesis with neutral Mo imido alkylidene N-heterocyclic carbene bistriflate complexes.
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Affiliation(s)
- Maren Podewitz
- Institute
of General, Inorganic and Theoretical Chemistry, and Center of Molecular
Biosciences, University of Innsbruck, Innrain 80/82, AT-6020 Innsbruck, Austria
| | - Suman Sen
- Institute
of Polymer Chemistry, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - Michael R. Buchmeiser
- Institute
of Polymer Chemistry, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
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24
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Toward E-selective Olefin Metathesis: Computational Design and Experimental Realization of Ruthenium Thio-Indolate Catalysts. Top Catal 2021. [DOI: 10.1007/s11244-021-01468-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AbstractThe selective transformation of 1-alkenes into E-olefins is a long-standing challenge in olefin metathesis. Density functional theory (DFT) calculations predict high E-selectivity for catalysts incorporating a bidentate, dianionic thio-indolate ligand within a RuXX’(NHC)(py)(= CHR) platform (NHC = N-heterocyclic carbene; py = pyridine). Such complexes are predicted to yield E-olefins by favoring anti-disposed substituents in the transition state expected to be rate-determining: specifically, that for cycloreversion of the metallacyclobutane intermediate. Three pyridine-stabilized catalysts Ru21a-c were synthesized, in which the thio-indolate ligand bears a H, Me, or Ph substituent at the C2 position, and the NHC ligand is the unsaturated imidazoline-2-ylidene Me2IMes (which bears N-mesityl groups and methyl groups on the C4,5 backbone). Single-crystal X-ray diffraction analysis of Ru21c confirms the ligand orientation required for E-selective metathesis, with the thio-indolate sulfur atom binding cis to the NHC, and the indolate nitrogen atom trans to the NHC. However, whereas the new complexes mediated metathetic exchange of their 2-thienylmethylidene ligand in the presence of the common metathesis substrates styrene and allylbenzene, no corresponding self-metathesis products were obtained. Only small amounts of 2-butene (73% (Z)-2-butene) were obtained in self-metathesis of propene using Ru21a. Detailed DFT analysis of this process revealed that product release is surprisingly slow, limiting the reaction rate and explaining the low metathesis activity. With the barrier to dissociation of (Z)-2-butene being lower than that of (E)-2-butene, the calculations also account for the observed Z-selectivity of Ru21a. These findings provide guidelines for catalyst redesign in pursuit of the ambitious goal of E-selective 1-alkene metathesis.
Graphic abstract
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25
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Nechmad NB, Kobernik V, Tarannam N, Phatake R, Eivgi O, Kozuch S, Lemcoff NG. Reactivity and Selectivity in Ruthenium Sulfur‐Chelated Diiodo Catalysts. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202014929] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Noy B. Nechmad
- Department of Chemistry Ben-Gurion University of the Negev Beer-Sheva 84105 Israel
| | - Victoria Kobernik
- Department of Chemistry Ben-Gurion University of the Negev Beer-Sheva 84105 Israel
| | - Naziha Tarannam
- Department of Chemistry Ben-Gurion University of the Negev Beer-Sheva 84105 Israel
| | - Ravindra Phatake
- Department of Chemistry Ben-Gurion University of the Negev Beer-Sheva 84105 Israel
| | - Or Eivgi
- Department of Chemistry Ben-Gurion University of the Negev Beer-Sheva 84105 Israel
| | - Sebastian Kozuch
- Department of Chemistry Ben-Gurion University of the Negev Beer-Sheva 84105 Israel
| | - N. Gabriel Lemcoff
- Department of Chemistry Ben-Gurion University of the Negev Beer-Sheva 84105 Israel
- Ilse Katz Institute for Nanotechnology Science Ben-Gurion University of the Negev Beer-Sheva 84105 Israel
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26
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Fürstner A. Lessons from Natural Product Total Synthesis: Macrocyclization and Postcyclization Strategies. Acc Chem Res 2021; 54:861-874. [PMID: 33507727 PMCID: PMC7893715 DOI: 10.1021/acs.accounts.0c00759] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
![]()
Macrocyclic
natural products are plentiful in
the bacteria, archaea,
and eukaryote domains of life. For the significant advantages that
they provide to the producing organisms, evolution has learned how
to implement various types of macrocyclization reactions into the
different biosynthetic pathways and how to effect them with remarkable
ease. Mankind greatly benefits from nature’s pool, not least
because naturally occurring macrocycles or derivatives thereof serve
as important drugs for the treatment of many serious ailments. In stark contrast, macrocyclization reactions are usually perceived
as difficult to accomplish by purely chemical means. While it is true
that ring closure necessarily entails an entropic loss and may result
in the buildup of (considerable) ring strain that must be compensated
for in one way or the other, it is also fair to note tremendous methodological
advances during the last decades that greatly alleviated this traditional
“macrocycle challenge”. It is therefore increasingly
possible to explore the advantages provided by large as well as medium-size
ring systems in a more systematic manner. This venture also holds
the promise of increasing the “chemical space” amenable
to drug development to a considerable extent. In consideration
of this and other important long-term perspectives,
it is appropriate to revisit the current state of the art. To this
end, a number of vignettes are presented, each of which summarizes
a total synthesis project targeting macrocyclic natural products of
greatly different chemotypes using a variety of transformations to
reach these goals. Although we were occasionally facing “dead
ends”, which are also delineated for the sake of a complete
picture, these case studies illustrate the notion that the formation
of a certain macrocyclic perimeter is (usually) no longer seriously
limiting. In addition to substantial progress in the “classical”
repertoire (macrolactonization and macrolactamization
(pateamine A, spirastrellolide, and belizentrin)), various metal-catalyzed
reactions have arguably led to the greatest leaps forward. Among them,
palladium-catalyzed C–C bond formation (roseophilin and nominal
xestocyclamine A) and, in particular, alkene and alkyne metathesis
stand out (iejimalide, spirastrellolide, enigmazole, ingenamine, and
sinulariadiolide). In some cases, different methods were pursued in
parallel, thus allowing for a critical assessment and comparison. To the extent that the macrocyclic challenge is vanishing, the
opportunity arises to focus attention on the postmacrocyclization
phase. One may stipulate that a well-designed cyclization precursor
does not only ensure efficient ring closure but also fosters and streamlines
the steps that come after the event. One way to do so is dual (multiple)
use in that the functional groups serving the actual cyclization reaction
also find productive applications downstream from it rather than being
subject to simple defunctionalization. In this context,
better insight into the conformational peculiarities of large rings
and the growing confidence in their accessibility in a stereochemically
well defined format rejuvenate the implementation of transannular
reactions or reaction cascades that can lead to rapid and substantial
increases in molecular complexity. The examples summarized herein
showcase such possibilities, with special emphasis on tranannular
gold catalysis and the emerging ruthenium-catalyzed trans-hydrometalation chemistry for the selective functionalization of
alkynes.
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27
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Fürstner A. Iron Catalyzed C–C-Bond Formation: From Canonical Cross Coupling to a Quest for New Reactivity. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20200319] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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28
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Nechmad NB, Kobernik V, Tarannam N, Phatake R, Eivgi O, Kozuch S, Lemcoff NG. Reactivity and Selectivity in Ruthenium Sulfur-Chelated Diiodo Catalysts. Angew Chem Int Ed Engl 2021; 60:6372-6376. [PMID: 33576565 DOI: 10.1002/anie.202014929] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 12/12/2020] [Indexed: 12/18/2022]
Abstract
A trifluoromethyl sulfur-chelated ruthenium benzylidene, Ru-S-CF3 -I, was synthesized and characterized. This latent precatalyst provides a distinct activity and selectivity profiles for olefin metathesis reactions depending on the substrate. For example, 1,3-divinyl-hexahydropentalene derivatives were efficiently obtained by ring-opening metathesis (ROM) of dicyclopentadiene (DCPD). Ru-S-CF3 -I also presented a much more effective photoisomerization process from the inactive cis-diiodo to the active trans-diiodo configuration after exposure to 510 nm (green light), allowing for a wide scope of photoinduced olefin metathesis reactions. DFT calculations suggest a faster formation and enhanced stability of the active trans-diiodo species of Ru-S-CF3 -I compared with Ru-S-Ph-I, explaining its higher reactivity. In addition, the photochemical release of chloride anions by irradiation of Cl-BODIPY in the presence of DCPD derivatives with diiodo Ru benzylidenes, led to in situ generation of chloride complexes, which quickly produced the corresponding cross-linked polymers. Thus, novel selective pathways that use visible light to guide olefin metathesis based synthetic sequences is presented.
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Affiliation(s)
- Noy B Nechmad
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Victoria Kobernik
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Naziha Tarannam
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Ravindra Phatake
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Or Eivgi
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Sebastian Kozuch
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - N Gabriel Lemcoff
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel.,Ilse Katz Institute for Nanotechnology Science, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
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29
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Gupta S, Sabbasani VR, Su S, Wink DJ, Lee D. Alkene-Chelated Ruthenium Alkylidenes: A Missing Link to New Catalysts. ACS Catal 2021. [DOI: 10.1021/acscatal.0c04972] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Saswata Gupta
- Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor St., Chicago, Illinois 60607, United States
| | - Venkata R. Sabbasani
- Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor St., Chicago, Illinois 60607, United States
| | - Siyuan Su
- Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor St., Chicago, Illinois 60607, United States
| | - Donald J. Wink
- Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor St., Chicago, Illinois 60607, United States
| | - Daesung Lee
- Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor St., Chicago, Illinois 60607, United States
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30
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Löffler LE, Wirtz C, Fürstner A. Collective Total Synthesis of Casbane Diterpenes: One Strategy, Multiple Targets. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202015243] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
| | - Conny Wirtz
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
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31
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Löffler LE, Wirtz C, Fürstner A. Collective Total Synthesis of Casbane Diterpenes: One Strategy, Multiple Targets. Angew Chem Int Ed Engl 2021; 60:5316-5322. [PMID: 33289954 PMCID: PMC7986786 DOI: 10.1002/anie.202015243] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Indexed: 11/29/2022]
Abstract
Of the more than 100 casbane diterpenes known to date, only the eponymous parent hydrocarbon casbene itself has ever been targeted by chemical synthesis. Outlined herein is a conceptually new approach that brings not a single but a variety of casbane derivatives into reach, especially the more highly oxygenated and arguably more relevant members of this family. The key design elements are a catalyst‐controlled intramolecular cyclopropanation with or without subsequent equilibration, chain extension of the resulting stereoisomeric cyclopropane building blocks by chemoselective hydroboration/cross‐coupling, and the efficient closure of the strained macrobicyclic framework by ring‐closing alkyne metathesis. A hydroxy‐directed catalytic trans‐hydrostannation allows for late‐stage diversity. These virtues are manifested in the concise total syntheses of depressin, yuexiandajisu A, and ent‐pekinenin C. The last compound turned out to be identical to euphorhylonal A, the structure of which had clearly been misassigned.
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Affiliation(s)
- Lorenz E Löffler
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim/Ruhr, Germany
| | - Conny Wirtz
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim/Ruhr, Germany
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32
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Schulthoff S, Hamilton JY, Heinrich M, Kwon Y, Wirtz C, Fürstner A. The Formosalides: Structure Determination by Total Synthesis. Angew Chem Int Ed Engl 2021; 60:446-454. [PMID: 32946141 PMCID: PMC7821135 DOI: 10.1002/anie.202011472] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Indexed: 01/08/2023]
Abstract
Total synthesis allowed the constitution of the cytotoxic marine macrolides of the formosalide family to be confirmed and their previously unknown stereostructure to be assigned with confidence. The underlying blueprint was inherently modular to ensure that each conceivable isomer could be reached. This flexibility derived from the use of strictly catalyst controlled transformations to set the stereocenters, except for the anomeric position, which is under thermodynamic control; as an extra safety measure, all stereogenic centers were set prior to ring closure to preclude any interference of the conformation adopted by the macrolactone rings of the different diastereomers. Late-stage macrocyclization by ring-closing alkyne metathesis was followed by a platinum-catalyzed transannular 6-exo-dig hydroalkoxylation/ketalization to craft the polycyclic frame. The side chain featuring a very labile unsaturation pattern was finally attached to the core by Stille coupling.
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Affiliation(s)
| | | | - Marc Heinrich
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Yonghoon Kwon
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Conny Wirtz
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
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33
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Fuwa H. Structure determination, correction, and disproof of marine macrolide natural products by chemical synthesis. Org Chem Front 2021. [DOI: 10.1039/d1qo00481f] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Integration of chemical synthesis, NMR spectroscopy, and various analytical means is key to success in the structure elucidation of stereochemically complex marine macrolide natural products.
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Affiliation(s)
- Haruhiko Fuwa
- Department of Applied Chemistry
- Faculty of Science and Engineering
- Chuo University
- Tokyo 112-8551
- Japan
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34
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Alvarez R, de Lera AR. Natural polyenic macrolactams and polycyclic derivatives generated by transannular pericyclic reactions: optimized biogenesis challenging chemical synthesis. Nat Prod Rep 2020; 38:1136-1220. [PMID: 33283831 DOI: 10.1039/d0np00050g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Covering from 1992 to the end of 2020-11-20.Genetically-encoded polyenic macrolactams, which are constructed by Nature using hybrid polyketide synthase/nonribosomal peptide synthase (PKSs/NRPSs) assembly lines, are part of the large collection of natural products isolated from bacteria. Activation of cryptic (i.e., silent) gene clusters in these microorganisms has more recently allowed to generate and eventually isolate additional members of the family. Having two unsaturated fragments separated by short saturated chains, the primary macrolactam is posited to undergo transannular reactions and further rearrangements thus leading to the generation of a structurally diverse collection of polycyclic (natural) products and oxidized derivatives. The review will cover the challenges that scientists face on the isolation of these unstable compounds from the cultures of the producing microorganisms, their structural characterization, biological activities, optimized biogenetic routes, as well as the skeletal rearrangements of the primary structures of the natural macrolactams derived from pericyclic reactions of the polyenic fragments. The efforts of the synthetic chemists to emulate Nature on the successful generation and structural confirmation of these natural products will also be reported.
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Affiliation(s)
- Rosana Alvarez
- Department of Organic Chemistry and Center for Biomedical Research (CINBIO), IBIV, Universidade de Vigo, 36310 Vigo, Spain.
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35
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Lai Y, Dai W. Modular Total Synthesis of (–)‐Palmyrolide A and (+)‐(
5
S
,
7
S
)‐Palmyrolide A via
Ring‐Closing
Metathesis and Alkene Isomerization†. CHINESE J CHEM 2020. [DOI: 10.1002/cjoc.202000458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yecai Lai
- Laboratory of Advanced Catalysis and Synthesis, Department of Chemistry and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Clear Water Bay Kowloon Hong Kong SAR China
| | - Wei‐Min Dai
- Laboratory of Advanced Catalysis and Synthesis, Department of Chemistry and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Clear Water Bay Kowloon Hong Kong SAR China
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36
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Xu Y, Wong JJ, Samkian AE, Ko JH, Chen S, Houk KN, Grubbs RH. Efficient Z-Selective Olefin-Acrylamide Cross-Metathesis Enabled by Sterically Demanding Cyclometalated Ruthenium Catalysts. J Am Chem Soc 2020; 142:20987-20993. [DOI: 10.1021/jacs.0c11334] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Yan Xu
- Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Jonathan J. Wong
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Adrian E. Samkian
- Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Jeong Hoon Ko
- Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Shuming Chen
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - K. N. Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Robert H. Grubbs
- Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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37
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Hillenbrand J, Leutzsch M, Gordon CP, Copéret C, Fürstner A. 183 W NMR Spectroscopy Guides the Search for Tungsten Alkylidyne Catalysts for Alkyne Metathesis. Angew Chem Int Ed Engl 2020; 59:21758-21768. [PMID: 32820864 PMCID: PMC7756321 DOI: 10.1002/anie.202009975] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/21/2020] [Indexed: 12/12/2022]
Abstract
Triarylsilanolates are privileged ancillary ligands for molybdenum alkylidyne catalysts for alkyne metathesis but lead to disappointing results and poor stability in the tungsten series. 1 H,183 W heteronuclear multiple bond correlation spectroscopy, exploiting a favorable 5 J-coupling between the 183 W center and the peripheral protons on the alkylidyne cap, revealed that these ligands upregulate the Lewis acidity to an extent that the tungstenacyclobutadiene formed in the initial [2+2] cycloaddition step is over-stabilized and the catalytic turnover brought to a halt. Guided by the 183 W NMR shifts as a proxy for the Lewis acidity of the central atom and by an accompanying chemical shift tensor analysis of the alkylidyne unit, the ligand design was revisited and a more strongly π-donating all-alkoxide ligand prepared. The new expanded chelate complex has a tempered Lewis acidity and outperforms the classical Schrock catalyst, carrying monodentate tert-butoxy ligands, in terms of rate and functional-group compatibility.
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Affiliation(s)
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Christopher P. Gordon
- Department of Chemistry and Applied BiosciencesETH ZürichVladimir-Prelog-Weg 1–58093ZürichSwitzerland
| | - Christophe Copéret
- Department of Chemistry and Applied BiosciencesETH ZürichVladimir-Prelog-Weg 1–58093ZürichSwitzerland
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
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38
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From Target-Oriented to Motif-Oriented: A Case Study on Nannocystin Total Synthesis. Molecules 2020; 25:molecules25225327. [PMID: 33203102 PMCID: PMC7697126 DOI: 10.3390/molecules25225327] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/09/2020] [Accepted: 11/11/2020] [Indexed: 01/14/2023] Open
Abstract
Natural product total synthesis is in essence target-oriented in that a set of organic transformations are orchestrated into a workable process, leading ultimately to the target molecule with a predefined architecture. For a bioactive lead, proof of synthetic viability is merely the beginning. Ensuing effort repurposes the initial synthesis for structural diversification in order to probe structure-activity relationship (SAR). Yet accessibility is not equal to flexibility; moving from convergency to divergency, it is not always feasible to explore the chemical space around a particular substructure of interest simply by tweaking an established route. In this situation, the motif-oriented strategy becomes a superior choice, which gives priority to synthetic flexibility at the concerned site such that a route is adopted only if it is capable of implementing diversification therein. This strategy was recently devised by Fürstner et al., enabling them to achieve total synthesis of both natural and non-natural nannocystins varied at an otherwise challenging position. The present review examines seven distinctive nannocystin total syntheses reported thus far and showcases the merits of conventional (target-oriented) as well as motif-oriented strategies, concluding that these two approaches complement each other and are both indispensable for natural product based drug discovery.
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39
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Schulthoff S, Hamilton JY, Heinrich M, Kwon Y, Wirtz C, Fürstner A. The Formosalides: Structure Determination by Total Synthesis. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202011472] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
| | | | - Marc Heinrich
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Yonghoon Kwon
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Conny Wirtz
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
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40
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Sakurai K, Sakamoto K, Sasaki M, Fuwa H. Unified Total Synthesis of (-)-Enigmazole A and (-)-15-O-Methylenigmazole A. Chem Asian J 2020; 15:3494-3502. [PMID: 32902874 DOI: 10.1002/asia.202001015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Indexed: 12/29/2022]
Abstract
The total synthesis of cytotoxic marine phosphomacrolides, (-)-enigmazole A and (-)-15-O-methylenigmazole A, is described in detail. The 2,6-cis-substituted tetrahydropyran ring was efficiently elaborated by using a tandem olefin cross-metathesis/intramolecular oxa-Michael addition reaction. The 18-membered macrolactone skeleton was forged via a Au-catalyzed propargylic benzoate rearrangement/macrocyclic ring-closing metathesis sequence. Late-stage diversification of a common intermediate enabled unified total synthesis of (-)-enigmazole A and (-)-15-O-methylenigmazole A.
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Affiliation(s)
- Keisuke Sakurai
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Keita Sakamoto
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan.,Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Makoto Sasaki
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Haruhiko Fuwa
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
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41
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Luo S, Huang X, Guo L, Huang P. Catalytic Asymmetric Total Synthesis of Macrocyclic Marine Natural Product (–)‐Haliclonin A
†. CHINESE J CHEM 2020. [DOI: 10.1002/cjoc.202000291] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Shi‐Peng Luo
- Department of Chemistry and The Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University Xiamen Fujian 361005 China
- School of Chemistry and Environmental Engineering, Jiangsu University of Technology Changzhou Jiangsu 213001 China
| | - Xiong‐Zhi Huang
- Department of Chemistry and The Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University Xiamen Fujian 361005 China
| | - Lian‐Dong Guo
- Department of Chemistry and The Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University Xiamen Fujian 361005 China
| | - Pei‐Qiang Huang
- Department of Chemistry and The Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University Xiamen Fujian 361005 China
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42
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Rivas A, Areal A, Mora P, Álvarez R, de Lera AR. Synthesis of Symmetrical and Nonsymmetrical Polyenes by Iterative and Bidirectional Palladium-Catalyzed Cross-Coupling Reactions. Chemistry 2020; 26:13543-13567. [PMID: 32267574 DOI: 10.1002/chem.202000624] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 04/08/2020] [Indexed: 11/06/2022]
Abstract
Bifunctional unsaturated reagents designed to undergo palladium-catalyzed cross-coupling reactions with complementary polyenyl connective fragments are highly useful for the undoubtedly challenging synthesis of polyenes. The current toolkit of building blocks for the bidirectional formation of Csp2 -Csp2 single bonds of polyenes includes homo-bisfunctionalized reagents with equal or unequal reactivity (due to steric and/or electronic factors), and hetero-bisfunctionalized counterparts containing either two different nucleophiles, two electrophiles or one of these functionalities and a latent nucleophile that can be unmasked when desired. The combination of these bifunctional linchpin reagents using tactics that modulate the reactivity of each terminus in order to achieve the required connection have streamlined the synthesis of polyenes of great complexity using (iterative) cross-coupling methods for Csp2 -Csp2 bond formation. Reaction conditions for the Pd-catalyzed cross-coupling reactions are mild and functional-group-tolerant, and therefore these protocols allow to construct the polyene structures using shorter unsaturated reactants with the desired geometries, since in general the products preserve the stereochemical information of the connected cross-coupling partners.
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Affiliation(s)
- Aurea Rivas
- Departamento de Química Orgánica, Facultade de Química, CINBIO and IIS Galicia Sur, Universidade de Vigo, 36310, Vigo, Spain
| | - Andrea Areal
- Departamento de Química Orgánica, Facultade de Química, CINBIO and IIS Galicia Sur, Universidade de Vigo, 36310, Vigo, Spain
| | - Paula Mora
- Departamento de Química Orgánica, Facultade de Química, CINBIO and IIS Galicia Sur, Universidade de Vigo, 36310, Vigo, Spain
| | - Rosana Álvarez
- Departamento de Química Orgánica, Facultade de Química, CINBIO and IIS Galicia Sur, Universidade de Vigo, 36310, Vigo, Spain
| | - Angel R de Lera
- Departamento de Química Orgánica, Facultade de Química, CINBIO and IIS Galicia Sur, Universidade de Vigo, 36310, Vigo, Spain
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43
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Hoveyda AH, Liu Z, Qin C, Koengeter T, Mu Y. Impact of Ethylene on Efficiency and Stereocontrol in Olefin Metathesis: When to Add It, When to Remove It, and When to Avoid It. Angew Chem Int Ed Engl 2020; 59:22324-22348. [DOI: 10.1002/anie.202010205] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 09/02/2020] [Indexed: 12/24/2022]
Affiliation(s)
- Amir H. Hoveyda
- Department of Chemistry Merkert Chemistry Center Boston College Chestnut Hill MA 02467 USA
- Supramolecular Science and Engineering Institute University of Strasbourg CNRS 67000 Strasbourg France
| | - Zhenxing Liu
- Supramolecular Science and Engineering Institute University of Strasbourg CNRS 67000 Strasbourg France
| | - Can Qin
- Department of Chemistry Merkert Chemistry Center Boston College Chestnut Hill MA 02467 USA
| | - Tobias Koengeter
- Department of Chemistry Merkert Chemistry Center Boston College Chestnut Hill MA 02467 USA
| | - Yucheng Mu
- Department of Chemistry Merkert Chemistry Center Boston College Chestnut Hill MA 02467 USA
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44
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Hoveyda AH, Liu Z, Qin C, Koengeter T, Mu Y. Impact of Ethylene on Efficiency and Stereocontrol in Olefin Metathesis: When to Add It, When to Remove It, and When to Avoid It. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202010205] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Amir H. Hoveyda
- Department of Chemistry Merkert Chemistry Center Boston College Chestnut Hill MA 02467 USA
- Supramolecular Science and Engineering Institute University of Strasbourg CNRS 67000 Strasbourg France
| | - Zhenxing Liu
- Supramolecular Science and Engineering Institute University of Strasbourg CNRS 67000 Strasbourg France
| | - Can Qin
- Department of Chemistry Merkert Chemistry Center Boston College Chestnut Hill MA 02467 USA
| | - Tobias Koengeter
- Department of Chemistry Merkert Chemistry Center Boston College Chestnut Hill MA 02467 USA
| | - Yucheng Mu
- Department of Chemistry Merkert Chemistry Center Boston College Chestnut Hill MA 02467 USA
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45
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Hillenbrand J, Leutzsch M, Gordon CP, Copéret C, Fürstner A. 183
W NMR Spectroscopy Guides the Search for Tungsten Alkylidyne Catalysts for Alkyne Metathesis. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009975] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Christopher P. Gordon
- Department of Chemistry and Applied Biosciences ETH Zürich Vladimir-Prelog-Weg 1–5 8093 Zürich Switzerland
| | - Christophe Copéret
- Department of Chemistry and Applied Biosciences ETH Zürich Vladimir-Prelog-Weg 1–5 8093 Zürich Switzerland
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
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46
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Hillenbrand J, van Gastel M, Bill E, Neese F, Fürstner A. Isolation of a Homoleptic Non-oxo Mo(V) Alkoxide Complex: Synthesis, Structure, and Electronic Properties of Penta- tert-Butoxymolybdenum. J Am Chem Soc 2020; 142:16392-16402. [PMID: 32847348 PMCID: PMC7517713 DOI: 10.1021/jacs.0c07073] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Treatment of [MoCl4(THF)2] with MOtBu (M = Na, Li) does not result in simple metathetic ligand exchange but entails disproportionation with formation of the well-known dinuclear complex [(tBuO)3Mo≡Mo(OtBu)3] and a new paramagnetic compound, [Mo(OtBu)5]. This particular five-coordinate species is the first monomeric, homoleptic, all-oxygen-ligated but non-oxo 4d1 Mo(V) complex known to date; as such, it proves that the dominance of the Mo═O group over (high-valent) molybdenum chemistry can be challenged. [Mo(OtBu)5] was characterized in detail by a combined experimental/computational approach using X-ray diffraction; UV/vis, MCD, IR, EPR, and NMR spectroscopy; and quantum chemistry. The recorded data confirm a Jahn-Teller distortion of the structure, as befitting a d1 species, and show that the complex undergoes Berry pseudorotation. The alkoxide ligands render the disproportionation reaction, leading the formation of [Mo(OtBu)5] to be particularly facile, even though the parent complex [MoCl4(THF)2] itself was also found to be intrinsically unstable; remarkably, this substrate converts into a crystalline material, in which the newly formed Mo(III) and Mo(V) products cohabitate the same unit cell.
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Affiliation(s)
| | | | - Eckhard Bill
- Max-Planck-Institute for Chemical Energy Conversion, 45470 Mülheim/Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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47
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Huang WY, Wang GQ, Li WH, Li TT, Ji GJ, Ren SC, Jiang M, Yan L, Tang HT, Pan YM, Ding YJ. Porous Ligand Creates New Reaction Route: Bifunctional Single-Atom Palladium Catalyst for Selective Distannylation of Terminal Alkynes. Chem 2020. [DOI: 10.1016/j.chempr.2020.06.020] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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48
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Meng Z, Fürstner A. Total Synthesis Provides Strong Evidence: Xestocyclamine A is the Enantiomer of Ingenamine. J Am Chem Soc 2020; 142:11703-11708. [PMID: 32544329 PMCID: PMC7467676 DOI: 10.1021/jacs.0c05347] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
![]()
Xestocyclamine
A ((−)-1) is featured prominently
in a biosynthesis pathway leading to a large family of polycyclic
alkaloids. The first total synthesis now proves that the structure
of this compound had originally been misassigned. The route to (−)-1 is based on a double Michael addition for the formation
of the bridged diazadecalin core and a palladium-catalyzed decarboxylative
allylation to install the quaternary bridgehead center. Ring-closing
alkyne metathesis allowed a 13-membered cycloalkyne to be forged,
which was selectively reduced during an involved sequence of hydroboration/selective
protodeborylation/alkyl-Suzuki coupling used to close the 11-membered
ring. Crystallographic data prove the identity of synthetic (−)-1 with nominal xestocyclamine, but the spectra differ from
those of the authentic alkaloid. To clarify the point, the synthesis
was redirected toward ingenamine (3), which is supposedly
a positional isomer of 1. The recorded data confirm the
assignment of this particular natural product and strongly suggest
that xestocyclamine A is in fact the enantiomer of ingenamine (+)-3.
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Affiliation(s)
- Zhanchao Meng
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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49
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Hillenbrand J, Leutzsch M, Yiannakas E, Gordon CP, Wille C, Nöthling N, Copéret C, Fürstner A. "Canopy Catalysts" for Alkyne Metathesis: Molybdenum Alkylidyne Complexes with a Tripodal Ligand Framework. J Am Chem Soc 2020; 142:11279-11294. [PMID: 32463684 PMCID: PMC7322728 DOI: 10.1021/jacs.0c04742] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
![]()
A new family of structurally well-defined
molybdenum alkylidyne
catalysts for alkyne metathesis, which is distinguished by a tripodal
trisilanolate ligand architecture, is presented. Complexes of type 1 combine the virtues of previous generations of silanolate-based
catalysts with a significantly improved functional group tolerance.
They are easy to prepare on scale; the modularity of the ligand synthesis
allows the steric and electronic properties to be fine-tuned and hence
the application profile of the catalysts to be optimized. This opportunity
is manifested in the development of catalyst 1f, which
is as reactive as the best ancestors but exhibits an unrivaled scope.
The new catalysts work well in the presence of unprotected alcohols
and various other protic groups. The chelate effect entails even a
certain stability toward water, which marks a big leap forward in
metal alkylidyne chemistry in general. At the same time, they tolerate
many donor sites, including basic nitrogen and numerous heterocycles.
This aspect is substantiated by applications to polyfunctional (natural)
products. A combined spectroscopic, crystallographic, and computational
study provides insights into structure and electronic character of
complexes of type 1. Particularly informative are a density
functional theory (DFT)-based chemical shift tensor analysis of the
alkylidyne carbon atom and 95Mo NMR spectroscopy; this
analytical tool had been rarely used in organometallic chemistry before
but turns out to be a sensitive probe that deserves more attention.
The data show that the podand ligands render a Mo-alkylidyne a priori
more electrophilic than analogous monodentate triarylsilanols; proper
ligand tuning, however, allows the Lewis acidity as well as the steric
demand about the central atom to be adjusted to the point that excellent
performance of the catalyst is ensured.
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Affiliation(s)
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Ektoras Yiannakas
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Christopher P Gordon
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5, 8093 Zürich, Switzerland
| | - Christian Wille
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Nils Nöthling
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Christophe Copéret
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5, 8093 Zürich, Switzerland
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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Heinrich M, Murphy JJ, Ilg MK, Letort A, Flasz JT, Philipps P, Fürstner A. Chagosensine: A Riddle Wrapped in a Mystery Inside an Enigma. J Am Chem Soc 2020; 142:6409-6422. [PMID: 32142305 PMCID: PMC7307910 DOI: 10.1021/jacs.0c01700] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Indexed: 01/02/2023]
Abstract
The marine macrolide chagosensine is supposedly distinguished by a (Z,Z)-configured 1,3-chlorodiene contained within a highly strained 16-membered lactone ring, which also incorporates two trans-2,5-disubstituted tetrahydrofuran (THF) rings; this array is unique. After our initial synthesis campaign had shown that the originally proposed structure is incorrect, the published data set was critically revisited to identify potential mis-assignments. The "northern" THF ring and the anti-configured diol in the "southern" sector both seemed to be sites of concern, thus making it plausible that a panel of eight diastereomeric chagosensine-like compounds would allow the puzzle to be solved. To meet the challenge, the preparation of the required building blocks was optimized, and a convergent strategy for their assembly was developed. A key role was played by the cobalt-catalyzed oxidative cyclization of alken-5-ol derivatives ("Mukaiyama cyclization"), which is shown to be exquisitely chemoselective for terminal alkenes, leaving even terminal alkynes (and other sites of unsaturation) untouched. Likewise, a palladium-catalyzed alkyne alkoxycarbonylation reaction with formation of an α-methylene-γ-lactone proved instrumental, which had not found application in natural product synthesis before. Further enabling steps were a nickel-catalyzed "Tamaru-type" homocrotylation, stereodivergent aldehyde homologations, radical hydroindation, and palladium-catalyzed alkyne-1,2-bis-stannation. The different building blocks were assembled in a serial fashion to give the idiosyncratic chlorodienes by an unprecedented site-selective Stille coupling followed by copper-mediated tin/chlorine exchange. The macrolactones were closed under forcing Yamaguchi conditions, and the resulting products were elaborated into the targeted compound library. Yet, only one of the eight diastereomers turned out to be stable in the solvent mixture that had been used to analyze the natural product; all other isomers were prone to ring opening and/or ring expansion. In addition to this stability issue, our self-consistent data set suggests that chagosensine has almost certainly little to do with the structure originally proposed by the isolation team.
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Affiliation(s)
| | | | - Marina K. Ilg
- Max-Planck-Institut für
Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
| | - Aurélien Letort
- Max-Planck-Institut für
Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
| | - Jakub T. Flasz
- Max-Planck-Institut für
Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
| | - Petra Philipps
- Max-Planck-Institut für
Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für
Kohlenforschung, D-45470 Mülheim/Ruhr, Germany
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