1
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Hess SN, Fürstner A. An Efficient and Scalable "Second Generation" Total Synthesis of the Marine Polyketide Limaol Endowed with Antiparasitic Activity. Chemistry 2024; 30:e202401429. [PMID: 38716817 DOI: 10.1002/chem.202401429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Indexed: 06/20/2024]
Abstract
The cluster of four skipped exo-methylene substituents on the "northern" wing of limaol renders this dinoflagellate-derived marine natural product unique in structural terms. This arguably non-thermodynamic array gains kinetic stability by virtue of populating local conformations which impede isomerization to a partly or fully conjugated polyene. This analysis suggested that the difficulties encountered during the late stages of our first total synthesis of this polyketide had not been caused by an overly fragile character of this unusual substructure; rather, an unfavorable steric microenvironment about the spirotricyclic core was identified as the likely cause. To remedy the issue, the protecting groups on this central fragment were changed; in effect, this amendment allowed all strategic and practical problems to be addressed. As a result, the overall yield over the longest linear sequence was multiplied by a factor of almost five and the material throughput increased more than eighty-fold per run. Key-to-success was a gold-catalyzed spirocyclization reaction; the reasons why a Brønsted acid cocatalyst is needed and the origin of the excellent levels of selectivity were delineated. The change of the protecting groups also allowed for much improved fragment coupling processes; most notably, the sequence of a substrate-controlled carbonyl addition reaction followed by Mitsunobu inversion that had originally been necessary to affix the southern tail to the core could be replaced by a reagent controlled asymmetric allylation. Finally, a much-improved route to the "northern" sector was established by leveraging the power of asymmetric hydrogenation of a 2-pyrone derivative. Limaol was found to combine appreciable antiparasitic activity with very modest cytotoxicity.
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Affiliation(s)
- Stephan N Hess
- 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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Karad SN, Saito H, Shimokawa J, Yorimitsu H. Regioselective Anti-Silyllithiation of Propargylic Alcohols. J Org Chem 2024; 89:3677-3683. [PMID: 36342367 DOI: 10.1021/acs.joc.2c01795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Among the known hydrosilylation or carbosilylation conditions of alkynes, anti-addition of the two units across the triple bond is considered rare compared to the syn counterpart. For anti-silylative vicinal difunctionalizations, transition-metal catalysts, such as ruthenium or palladium complexes, are generally required. Accordingly, silyl alkali metals have not been employed for those anti-addition transformations. Here we demonstrate that silyllithiums can add across the triple bond of a series of propargylic alkoxides regioselectively in an anti-fashion. Upon treatment with a variety of electrophiles, the trisubstituted alkenyl lithium intermediates were transformed into highly functionalized β-silyl allylic alcohols with high regiocontrol, eventually providing tri- or tetrasubstituted alkenylsilanes stereoselectively. A classic trick for anti-addition with propargylic alkoxides has transformed anti-silylative functionalizations into a robust and reliable strategy.
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Affiliation(s)
- Somnath N Karad
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Hayate Saito
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Jun Shimokawa
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Hideki Yorimitsu
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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3
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Jeon H, Kim JH, Kim S. Recent asymmetric synthesis of natural products bearing an α-tertiary amine moiety via temporary chirality induction strategies. Nat Prod Rep 2024; 41:228-250. [PMID: 37846620 DOI: 10.1039/d3np00032j] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
Covering: 2013 to 2023The α-tertiary amine moiety is a common structural motif in natural alkaloids and is frequently associated with intriguing biological activities and inherent synthetic challenges. A major hurdle in the total synthesis of these alkaloids is the asymmetric construction of the α-tertiary amine moiety. Temporary chirality inductions have been effective strategies employed to address this issue, particularly in natural product synthesis. The temporary chirality induction strategies in α-tertiary amine synthesis can be broadly classified into three categories based on the types of temporary chirality involved: Seebach's self-regeneration of stereocenters (SRS), C-to-N-to-C chirality transfer, and memory of chirality (MOC). This review highlights the recent advancements in temporary chirality induction strategies for the total synthesis of α-tertiary amine-containing natural products between 2013 and 2023.
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Affiliation(s)
- Hongjun Jeon
- Therapeutics & Biotechnology Division, Korea Research Institute of Chemical Technology (KRICT), Daejeon 34114, Republic of Korea
| | - Jae Hyun Kim
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Sanghee Kim
- College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea.
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4
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Rogova T, Ahrweiler E, Schoetz MD, Schoenebeck F. Recent Developments with Organogermanes: their Preparation and Application in Synthesis and Catalysis. Angew Chem Int Ed Engl 2024; 63:e202314709. [PMID: 37899306 DOI: 10.1002/anie.202314709] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 10/26/2023] [Accepted: 10/29/2023] [Indexed: 10/31/2023]
Abstract
Within the sphere of traditional Pd0 /PdII cross coupling reactions, organogermanes have been historically outperformed both in terms of scope and reactivity by more conventional transmetalating reagents. Subsequently, this class of compounds has been largely underutilized as a coupling partner in bond-forming strategies. Most recent studies, however, have shown that alternative modes of activation of these notoriously robust building blocks transform organogermanes into the most reactive site of the molecule-capable of outcompeting other functional groups (such as boronic acids, esters and silanes) for both C-C and C-heteroatom bond formation. As a result, over the past few years, the literature has increasingly featured methodologies that explore the potential of organogermanes as chemoselective and orthogonal coupling partners. Herein we highlight some of these recent advances in the field of organogermane chemistry both with respect to their synthesis and applications in synthetic and catalytic transformations.
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Affiliation(s)
- Tatiana Rogova
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Eric Ahrweiler
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Markus D Schoetz
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Franziska Schoenebeck
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
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5
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Broniarz K, Hreczycho G. Access to Unsaturated Organogermanes via (De)Hydrosilylation Mediated by Cobalt Complexes. Org Lett 2023; 25:6528-6533. [PMID: 37646486 PMCID: PMC10496132 DOI: 10.1021/acs.orglett.3c02326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Indexed: 09/01/2023]
Abstract
The functionalization of alkynylgermanes using hydrosilanes was accomplished by employing cobalt catalysis. Depending on the reactants used, the reaction can proceed via dehydrogenative coupling or hydrosilylation. Importantly, the presented method is characterized by mild reaction conditions, allowing rapid access to a wide range of organogermanes.
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Affiliation(s)
- Konstancja Broniarz
- Faculty of Chemistry, Adam
Mickiewicz University, Uniwersytetu Poznanskiego St. 8, 61-614 Poznan, Poland
| | - Grzegorz Hreczycho
- Faculty of Chemistry, Adam
Mickiewicz University, Uniwersytetu Poznanskiego St. 8, 61-614 Poznan, Poland
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6
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Fürstner A. How to Break the Law:
trans
‐Hydroboration and
gem
‐Hydroboration of Alkynes. Isr J Chem 2023. [DOI: 10.1002/ijch.202300004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Affiliation(s)
- Alois Fürstner
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
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7
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Wang C, Wu J, Yan B, Ni C, Ma X, Yang Z. N
‐coordinated Aluminum Complexes Catalyze the Hydrostannation of Alkynes. ChemistrySelect 2023. [DOI: 10.1002/slct.202204405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Chengzhi Wang
- School of Chemistry and Chemical Engineering Beijing Institute of Technology Beijing 100081 P. R. China
| | - Jin Wu
- Xi'an Aerospace Propulsion Test Technique Institute Xi'an 710100 P. R. China
| | - Ben Yan
- School of Chemistry and Chemical Engineering Beijing Institute of Technology Beijing 100081 P. R. China
| | - Congjian Ni
- School of Chemistry and Chemical Engineering Beijing Institute of Technology Beijing 100081 P. R. China
| | - Xiaoli Ma
- School of Chemistry and Chemical Engineering Beijing Institute of Technology Beijing 100081 P. R. China
| | - Zhi Yang
- School of Chemistry and Chemical Engineering Beijing Institute of Technology Beijing 100081 P. R. China
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8
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Dhankhar J, Hofer MD, Linden A, Čorić I. Site-Selective C-H Arylation of Diverse Arenes Ortho to Small Alkyl Groups. Angew Chem Int Ed Engl 2022; 61:e202205470. [PMID: 35830351 DOI: 10.1002/anie.202205470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Indexed: 01/07/2023]
Abstract
Catalytic systems for direct C-H activation of arenes commonly show preference for electronically activated and sterically exposed C-H sites. Here we show that a range of functionally rich and pharmaceutically relevant arene classes can undergo site-selective C-H arylation ortho to small alkyl substituents, preferably endocyclic methylene groups. The C-H activation is experimentally supported as being the selectivity-determining step, while computational studies of the transition state models indicate the relevance of non-covalent interactions between the catalyst and the methylene group of the substrate. Our results suggest that preference for C(sp2 )-H activation next to alkyl groups could be a general selectivity mode, distinct from common steric and electronic factors.
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Affiliation(s)
- Jyoti Dhankhar
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Micha D Hofer
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Anthony Linden
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Ilija Čorić
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
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9
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Isaac CJ, Miloserdov FM, Pécharman AF, Lowe JP, McMullin CL, Whittlesey MK. Structure and Reactivity of [Ru–Al] and [Ru–Sn] Heterobimetallic PPh 3-Based Complexes. Organometallics 2022; 41:2716-2730. [PMID: 36249448 PMCID: PMC9554919 DOI: 10.1021/acs.organomet.2c00344] [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: 07/08/2022] [Indexed: 11/30/2022]
Abstract
![]()
Treatment of [Ru(PPh3)(C6H4PPh2)2H][Li(THF)2] with AlMe2Cl and SnMe3Cl leads to elimination of LiCl and
CH4 and formation of the heterobimetallic complexes [Ru(C6H4PPh2)2{PPh2C6H4AlMe(THF)}H] 5 and [Ru(PPh3)(C6H4PPh2)(PPh2C6H4SnMe2)] 6, respectively.
The pathways to 5 and 6 have been probed
by variable temperature NMR studies, together with input from DFT
calculations. Complete reaction of H2 occurs with 5 at 60 °C and with 6 at room temperature
to yield the spectroscopically characterized trihydride complexes
[Ru(PPh2)2{PPh2C6H4AlMe}H3] 7 and [Ru(PPh2)2{PPh2C6H4SnMe2}H3] 8. In the presence of CO, 6 forms the acylated phosphine complex, [Ru(CO)2(C(O)C6H4PPh2)(PPh2C6H4SnMe2)] 9, through a series
of intermediates that were identified by NMR spectroscopy in conjunction
with 13CO labeling. Complex 6 undergoes addition
and substitution reactions with the N-heterocyclic carbene 1,3,4,5-tetramethylimidazol-2-ylidene
(IMe4) to give [Ru(IMe4)2(PPh2C6H4)(PPh2C6H4SnMe2)] 10, which converted via rare
N-Me group C–H activation to [Ru(IMe4)(PPh3)(IMe4)′(PPh2C6H4SnMe2)] 11 upon heating at 60 °C and
to a mixture of [Ru(IMe4)2(IMe4)′(PPh2C6H4SnMe2)] 12 and [Ru(PPh3)(PPh2C6H4)(IMe4-SnMe2)′] 13 at 120
°C.
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Affiliation(s)
- Connie J. Isaac
- Department of Chemistry, University of Bath, Bath BA2 7AY, U.K
| | | | | | - John P. Lowe
- Department of Chemistry, University of Bath, Bath BA2 7AY, U.K
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10
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Site‐Selective C–H Arylation of Diverse Arenes Ortho to Small Alkyl Groups. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202205470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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11
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Radkowski K, Fürstner A. A Sphingolipid Fatty Acid Constituent Made by Alkyne trans‐Hydrogenation: Total Synthesis of Symbioramide. Adv Synth Catal 2022. [DOI: 10.1002/adsc.202200540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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12
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Biberger T, Nöthling N, Leutzsch M, Gordon CP, Copéret C, Fürstner A. An Anionic Dinuclear Ruthenium Dihydrogen Complex of Relevance for Alkyne
gem
‐Hydrogenation. Angew Chem Int Ed Engl 2022; 61:e202201311. [PMID: 35363926 PMCID: PMC9322539 DOI: 10.1002/anie.202201311] [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: 01/24/2022] [Indexed: 11/12/2022]
Abstract
During an investigation into the fate of ruthenium precatalysts used for light‐driven alkyne gem‐hydrogenation reactions with formation of Grubbs‐type ruthenium catalysts, it was found that the reaction of [(IPr)(η6‐cymene)RuCl2] with H2 under UV‐irradiation affords an anionic dinuclear σ‐dihydrogen complex, which is thermally surprisingly robust. Not only are anionic σ‐complexes in general exceedingly rare, but the newly formed species seems to be the first example lacking any structural attributes able to counterbalance the negative charge and, in so doing, prevent oxidative insertion of the metal centers into the ligated H2 from occurring.
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Affiliation(s)
- Tobias Biberger
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Nils Nöthling
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - 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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13
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Bisht R, Haldar C, Hassan MMM, Hoque ME, Chaturvedi J, Chattopadhyay B. Metal-catalysed C-H bond activation and borylation. Chem Soc Rev 2022; 51:5042-5100. [PMID: 35635434 DOI: 10.1039/d1cs01012c] [Citation(s) in RCA: 72] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Transition metal-catalysed direct borylation of hydrocarbons via C-H bond activation has received a remarkable level of attention as a popular reaction in the synthesis of organoboron compounds owing to their synthetic versatility. While controlling the site-selectivity was one of the most challenging issues in these C-H borylation reactions, enormous efforts of several research groups proved instrumental in dealing with selectivity issues that presently reached an impressive level for both proximal and distal C-H bond borylation reactions. For example, in the case of ortho C-H bond borylation reactions, innovative methodologies have been developed either by the modification of the directing groups attached with the substrates or by creating new catalytic systems via the design of new ligand frameworks. Whereas meta and para selective C-H borylations remained a formidable challenge, numerous innovative concepts have been developed within a very short period of time by the development of new catalytic systems with the employment of various noncovalent interactions. Moreover, significant advancements have occurred for aliphatic C(sp3)-H borylations as well as enantioselective borylations. In this review article, we aim to discuss and summarize the different approaches and findings related to the development of directed proximal ortho, distal meta/para, aliphatic (racemic and enantioselective) borylation reactions since 2014. Additionally, considering the C-H borylation reaction as one of the most important mainstream reactions, various applications of this C-H borylation reaction toward the synthesis of natural products, therapeutics, and applications in materials chemistry will be summarized in the last part of this review article.
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Affiliation(s)
- Ranjana Bisht
- Center of Bio-Medical Research, Division of Molecular Synthesis & Drug Discovery, SGPGIMS Campus, Raebareli Road, Lucknow 226014, Uttar Pradesh, India.
| | - Chabush Haldar
- Center of Bio-Medical Research, Division of Molecular Synthesis & Drug Discovery, SGPGIMS Campus, Raebareli Road, Lucknow 226014, Uttar Pradesh, India.
| | - Mirja Md Mahamudul Hassan
- Center of Bio-Medical Research, Division of Molecular Synthesis & Drug Discovery, SGPGIMS Campus, Raebareli Road, Lucknow 226014, Uttar Pradesh, India.
| | - Md Emdadul Hoque
- Center of Bio-Medical Research, Division of Molecular Synthesis & Drug Discovery, SGPGIMS Campus, Raebareli Road, Lucknow 226014, Uttar Pradesh, India.
| | - Jagriti Chaturvedi
- Center of Bio-Medical Research, Division of Molecular Synthesis & Drug Discovery, SGPGIMS Campus, Raebareli Road, Lucknow 226014, Uttar Pradesh, India.
| | - Buddhadeb Chattopadhyay
- Center of Bio-Medical Research, Division of Molecular Synthesis & Drug Discovery, SGPGIMS Campus, Raebareli Road, Lucknow 226014, Uttar Pradesh, India.
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14
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Caló FP, Zimmer A, Bistoni G, Fürstner A. From Serendipity to Rational Design: Heteroleptic Dirhodium Amidate Complexes for Diastereodivergent Asymmetric Cyclopropanation. J Am Chem Soc 2022; 144:7465-7478. [PMID: 35420801 PMCID: PMC9052758 DOI: 10.1021/jacs.2c02258] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
![]()
A heteroleptic dirhodium
paddlewheel complex comprising three chiral
carboxylate ligands and one achiral acetamidate ligand has recently
been found to be uniquely effective in catalyzing the asymmetric cyclopropanation
of olefins with α-stannylated (silylated and germylated) α-diazoacetate
derivatives. A number of control experiments in combination with detailed
computational studies provide compelling evidence that an interligand
hydrogen bond between the −NH group of the amidate and the
ester carbonyl group of the reactive rhodium carbene intermediate
plays a quintessential role in the stereodetermining transition state.
The penalty for distorting this array outweighs steric arguments and
renders two of the four conceivable transitions states unviable. Based
on this mechanistic insight, the design of the parent catalyst is
revisited herein: placement of appropriate peripheral substituents
allows high levels of diastereocontrol to be imposed upon cyclopropanation,
which the original catalyst lacks. Because the new complexes allow
either trans- or cis-configured stannylated cyclopropanes to be made
selectively and in excellent optical purity, this transformation also
marks a rare case of diastereodivergent asymmetric catalysis. The
products are amenable to stereospecific cross coupling with aryl halides
or alkenyl triflates; these transformations appear to be the first
examples of the formation of stereogenic quaternary carbon centers
by the Stille reaction; carbonylative coupling is also achieved. Moreover,
tin/lithium exchange affords chiral lithium enolates, which can be
intercepted with a variety of electrophilic partners. The virtues
and inherent flexibility of this new methodology are illustrated by
an efficient synthesis of two salinilactones, extremely scarce bacterial
metabolites with signaling function involved in the self-regulatory
growth inhibition of the producing strain.
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Affiliation(s)
| | - Anne Zimmer
- Max-Planck-Institut für Kohlenforschung, Mülheim/Ruhr D-45470, Germany
| | - Giovanni Bistoni
- Max-Planck-Institut für Kohlenforschung, Mülheim/Ruhr D-45470, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, Mülheim/Ruhr D-45470, Germany
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15
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Biberger T, Nöthling N, Leutzsch M, Gordon CP, Copéret C, Fürstner A. An Anionic Dinuclear Ruthenium Dihydrogen Complex of Relevance for Alkyne gem‐Hydrogenation. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202201311] [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)
- Tobias Biberger
- Max-Planck-Institut für Kohlenforschung: Max-Planck-Institut fur Kohlenforschung Organometallc Chemistry 45470 Mülheim/Ruhr GERMANY
| | - Nils Nöthling
- Max-Planck-Institut für Kohlenforschung: Max-Planck-Institut fur Kohlenforschung Chemical Crystallography 45470 Mülheim/Ruhr GERMANY
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung: Max-Planck-Institut fur Kohlenforschung NMR Spectroscopy 45470 Mülheim/Ruhr GERMANY
| | - Christopher P. Gordon
- ETH Zürich: Eidgenossische Technische Hochschule Zurich Inorganic Chemistry 8093 Zürich SWITZERLAND
| | - Christophe Copéret
- ETH Zürich: Eidgenossische Technische Hochschule Zurich Inorganic Chemistry 8093 Zürich SWITZERLAND
| | - Alois Fürstner
- Max-Planck-Institut fur Kohlenforschung Organometallic Chemistry Kaiser-Wilhelm-Platz 1 45470 Mülheim/Ruhr GERMANY
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16
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Kassamba S, Perez-Luna A, Ferreira F, Durandetti M. Modular access to substituted germoles by intramolecular germylzincation. Chem Commun (Camb) 2022; 58:3901-3904. [PMID: 35234232 DOI: 10.1039/d1cc07163g] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Intramolecular alkyne germylzincation giving access to a wide range of germoles is achieved from triarylhydrogermanes in the presence of diethylzinc and AIBN as radical initiator. The reaction proceeds through activation of the Ge-H bond, leading to a heteroarylzinc intermediate after cyclisation, which can then be involved in a post-functionalisation reaction. Our results show that only 5-endo-dig cyclizations occur, with benzogermoles being exclusively obtained.
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Affiliation(s)
- Seydou Kassamba
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, Laboratoire COBRA (UMR 6014 & FR 3038), 76000 Rouen, France.
| | - Alejandro Perez-Luna
- Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, F-75005 Paris, France
| | - Franck Ferreira
- Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, F-75005 Paris, France
| | - Muriel Durandetti
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, Laboratoire COBRA (UMR 6014 & FR 3038), 76000 Rouen, France.
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17
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Peil S, Gutiérrez González A, Leutzsch M, Fürstner A. C-H Insertion via Ruthenium Catalyzed gem-Hydrogenation of 1,3-Enynes. J Am Chem Soc 2022; 144:4158-4167. [PMID: 35170941 PMCID: PMC8915261 DOI: 10.1021/jacs.1c13446] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
![]()
gem-Hydrogenation of an internal alkyne with the
aid of [Cp*RuCl]4 as the precatalyst is a highly unorthodox
transformation, in which one C atom of the triple bond is transformed
into a methylene group, whereas the second C atom gets converted into
a ruthenium carbene. In the case of 1,3-enynes bearing a propargylic
steering substituent as the substrates, the reaction occurs regioselectively,
giving rise to vinyl carbene complexes that adopt interconverting
η1/η3-binding modes in solution;
a prototypical example of such a reactive intermediate was characterized
in detail by spectroscopic means. Although both forms are similarly
stable, only the η3-vinyl carbene proved kinetically
competent to insert into primary, secondary, or tertiary C–H
bonds on the steering group itself or another suitably placed ether,
acetal, orthoester, or (sulfon)amide substituent. The ensuing net
hydrogenative C–H insertion reaction is highly enabling in
that it gives ready access to spirocyclic as well as bridged ring
systems of immediate relevance as building blocks for medicinal chemistry.
Moreover, the reaction scales well and lends itself to the formation
of partly or fully deuterated isotopologues. Labeling experiments
in combination with PHIP NMR spectroscopy (PHIP = parahydrogen induced
polarization) confirmed that the reactions are indeed triggered by gem-hydrogenation, whereas kinetic data provided valuable
insights into the very nature of the turnover-limiting transition
state of the actual C–H insertion step.
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Affiliation(s)
- Sebastian Peil
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | | | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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18
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Revealing 2-Dimethylhydrazino-2-alkyl alkynyl sphingosine derivatives as Sphingosine Kinase 2 inhibitors: some hints on the structural basis for selective inhibition. Bioorg Chem 2022; 121:105668. [DOI: 10.1016/j.bioorg.2022.105668] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 02/02/2022] [Accepted: 02/07/2022] [Indexed: 12/29/2022]
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19
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Biberger T, Hess SN, Leutzsch M, Fürstner A. Hydrogenative Cycloisomerization and Sigmatropic Rearrangement Reactions of Cationic Ruthenium Carbenes Formed by Catalytic Alkyne
gem
‐Hydrogenation. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202113827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Tobias Biberger
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Stephan N. Hess
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
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20
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Biberger T, Hess SN, Leutzsch M, Fürstner A. Hydrogenative Cycloisomerization and Sigmatropic Rearrangement Reactions of Cationic Ruthenium Carbenes Formed by Catalytic Alkyne gem-Hydrogenation. Angew Chem Int Ed Engl 2021; 61:e202113827. [PMID: 34911159 PMCID: PMC9306539 DOI: 10.1002/anie.202113827] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Indexed: 11/10/2022]
Abstract
gem‐Hydrogenation of propargyl alcohol derivatives with [CpXRu(MeCN)3]PF6 (CpX=substituted cyclopentadienyl) as catalysts affords cationic pianostool ruthenium carbene complexes which are so electrophilic that they attack a tethered olefin to furnish cyclopentene products; cyclopropanation or metathesis do not compete with this novel transformation. If the transient carbenes carry appropriate propargylic substituents, however, they engage in ([2,3]‐sigmatropic) rearrangements to give enol esters (carbonates, carbamates, sulfonates) or alkenyl halides. Both pathways are unprecedented in the vast hydrogenation literature. The proposed mechanistic scenarios are in line with labeling experiments and spectroscopic data; most notably, PHIP NMR spectroscopy (PHIP=parahydrogen induced polarization) provides compelling evidence that the reactions are indeed triggered by highly unorthodox gem‐hydrogenation events.
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Affiliation(s)
- Tobias Biberger
- Max-Planck-Institut für Kohlenforschung: Max-Planck-Institut fur Kohlenforschung, Organometallic Chemistry, GERMANY
| | - Stephan N Hess
- Max-Planck-Institut für Kohlenforschung: Max-Planck-Institut fur Kohlenforschung, Organometallic Chemistry, GERMANY
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung: Max-Planck-Institut fur Kohlenforschung, NMR Spectroscopy, GERMANY
| | - Alois Fürstner
- Max-Planck-Institut fur Kohlenforschung, Organometallic Chemistry, Kaiser-Wilhelm-Platz 1, 45470, Mülheim/Ruhr, GERMANY
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21
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Späth G, Fürstner A. Total Synthesis of Mycinamicin IV as Integral Part of a Collective Approach to Macrolide Antibiotics. Chemistry 2021; 28:e202104400. [PMID: 34910333 PMCID: PMC9305142 DOI: 10.1002/chem.202104400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Indexed: 11/09/2022]
Abstract
The total synthesis of the 16‐membered macrolide mycinamicin IV is outlined, which complements our previously disclosed, largely catalysis‐based route to the aglycone. This work must also be seen in the context of our recent conquest of aldgamycin N, a related antibiotic featuring a similar core but a distinctly different functionalization pattern. Taken together, these projects prove that the underlying blueprint is integrative and hence qualifies for a collective approach to this prominent class of natural products. In both cases, the final glycosylation phase mandated close attention and was accomplished only after robust de novo syntheses of the (di)deoxy sugars of the desosamine, chalcose, mycinose and aldgarose types had been established. Systematic screening of the glycosidation promoter was also critically important for success.
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Affiliation(s)
- Georg Späth
- Max-Planck-Institut für Kohlenforschung, Organometallic Chemistry, 45470, Mülheim/Ruhr, GERMANY
| | - Alois Fürstner
- Max-Planck-Institut fur Kohlenforschung, Organometallic Chemistry, Kaiser-Wilhelm-Platz 1, 45470, Mülheim/Ruhr, GERMANY
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22
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Steiniger KA, Lambert TH. Primary Alcohols via Nickel Pentacarboxycyclopentadienyl Diamide Catalyzed Hydrosilylation of Terminal Epoxides. Org Lett 2021; 23:8013-8017. [PMID: 34613745 DOI: 10.1021/acs.orglett.1c03029] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The efficient and regioselective hydrosilylation of epoxides co-catalyzed by a pentacarboxycyclopentadienyl (PCCP) diamide nickel complex and Lewis acid is reported. This method allows for the reductive opening of terminal, monosubstituted epoxides to form unbranched, primary alcohols. A range of substrates including both terminal and nonterminal epoxides are shown to work, and a mechanistic rationale is provided. This work represents the first use of a PCCP derivative as a ligand for transition-metal catalysis.
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Affiliation(s)
- Keri A Steiniger
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Tristan H Lambert
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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23
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Sharma A, Athe S, P.I R, Vishali K, Ghosh S. Total synthesis of the proposed structure of metacridamide B. Tetrahedron Lett 2021. [DOI: 10.1016/j.tetlet.2021.153374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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24
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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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25
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Zhu SF, He P, Hu MY, Zhang XY. Transition-Metal-Catalyzed Stereo- and Regioselective Hydrosilylation of Unsymmetrical Alkynes. SYNTHESIS-STUTTGART 2021. [DOI: 10.1055/a-1605-9572] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AbstractAlkyne hydrosilylation is one of the most efficient methods for the synthesis of alkenyl silicon derivatives and has been a hot topic of research for decades. This short review summarizes the progress in transition-metal-catalyzed stereo- and regioselective hydrosilylation of unsymmetrical alkynes. Topics are discussed based on different types of alkynes and the selectivities.1 Introduction2 Terminal Alkyne Hydrosilylation2.1 β-E Selectivity2.2 β-Z Selectivity2.3 α-selectivity3 Internal Alkyne Hydrosilylation3.1 Aryl–Alkyl Acetylenes3.2 Alkyl–Alkyl Acetylenes3.3 Internal Alkynes with Polarized Substituents4 Summary and Outlook
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26
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Song Y, Kim JH, Kim YC, Kim S. Asymmetric Total Synthesis of Oxazolomycins B and C. Chemistry 2021; 27:10731-10736. [PMID: 33999453 DOI: 10.1002/chem.202101341] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Indexed: 11/08/2022]
Abstract
Efforts towards the first total synthesis of (-)-oxazolomycin B and (+)-oxazolomycin C from the intermediate of our previous synthesis of (+)-neoxazolomycin are reported. The syntheses were achieved in a longest linear sequence of 25 steps from the amino acid serine in 3.6 and 2.7 % overall yields, respectively. The efficiency of our approach is derived from silyl triflate-mediated reductive oxazolidine ring-opening and Fürstner's Ru-catalyzed hydrosilylation and protodesilylation reactions. The obtained spectra and optical rotations were in good agreement with those of natural products, thus confirming the structures.
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Affiliation(s)
- Yeonghun Song
- College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Jae Hyun Kim
- College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea.,College of Pharmacy, Kangwon National University, 1 Kangwondaehak-gil, Chuncheon, Gangwon-do, 24341, Republic of Korea
| | - Young Chan Kim
- College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Sanghee Kim
- College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
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27
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Gao W, Ding H, Yu T, Wang Z, Ding S. Iridium-catalyzed regioselective hydrosilylation of internal alkynes facilitated by directing and steric effects. Org Biomol Chem 2021; 19:6216-6220. [PMID: 34195740 DOI: 10.1039/d1ob00910a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Here we reported the iridium-catalyzed hydrosilylation of internal alkynes under simple and mild conditions. The intrinsic functional groups of alkyne substrates were disclosed to be crucial in facilitating both the hydrosilylation process and related regioselectivity owing to their coordination capability towards the iridium catalyst. Utilization of the steric trimethylsilyl-protected trihydroxysilane proved to be another critical factor in ensuring the efficient proceeding of this process.
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Affiliation(s)
- Weiwei Gao
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
| | - Huan Ding
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
| | - Tian Yu
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
| | - Zhen Wang
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
| | - Shengtao Ding
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
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28
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Melot R, Saiegh TJ, Fürstner A. Regioselective trans-Hydrostannation of Boron-Capped Alkynes. Chemistry 2021; 27:17002-17011. [PMID: 34240757 PMCID: PMC9291331 DOI: 10.1002/chem.202101901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Indexed: 01/16/2023]
Abstract
Alkynyl‐B(aam) (aam=anthranilamidato) derivatives are readily available bench‐stable compounds that undergo remarkably selective reactions with Bu3SnH in the presence of [Cp*RuCl]4 as the catalyst. The addition follows a stereochemically unorthodox trans‐selective course; in terms of regioselectivity, the Bu3Sn‐ unit is delivered with high fidelity to the C‐atom of the triple bond adjacent to the boracyclic head group (“alpha,trans‐addition”). This outcome is deemed to reflect a hydrogen bonding interaction between the protic −NH groups of the benzo‐1,3,2‐diazaborininone ring system and the polarized [Ru−Cl] bond in the loaded catalyst, which locks the substrate in place in a favorable orientation relative to the incoming reagent. The resulting isomerically (almost) pure gem‐dimetalated building blocks are amenable to numerous downstream functionalizations; most remarkable is the ability to subject the −B(aam) moiety to Suzuki‐Miyaura cross coupling without need for prior hydrolysis while keeping the adjacent Bu3Sn‐ group intact. Alternatively, the tin residue can be engaged in selective tin/halogen exchange without touching the boron substituent; the fact that the two ‐NH entities of −B(aam) do not protonate organozinc reagents and hence do not interfere with Negishi reactions of the alkenyl halides thus formed is another virtue of this so far underutilized boracycle. Overall, the ruthenium catalyzed trans‐hydrostannation of alkynyl‐B(aam) derivatives opens a practical gateway to isomerically pure trisubstituted alkenes of many different substitution patterns by sequential functionalization of the 1‐alkenyl‐1,1‐heterobimetallic adducts primarily formed.
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Affiliation(s)
- Romain Melot
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany
| | - Tomas J Saiegh
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany
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29
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de la Vega-Hernández K, Chemla F, Ferreira F, Jackowski O, Perez-Luna A. Radical Germylzincation of Aryl- and Alkyl-Substituted Internal Alkynes. Org Lett 2021; 23:4426-4430. [PMID: 34032457 DOI: 10.1021/acs.orglett.1c01367] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The stereoselective germylzincation of internal alkynes delivering trisubstituted vinylgermanes is achieved via a radical chain process involving Ph3GeH and Et2Zn with AIBN as the initiator. Excellent levels of regiocontrol are observed for nonsymmetric (aryl, alkyl)-substituted alkynes and for propargylic alcohols with aryl-, alkyl-, or silyl-substituted alkynes. The germylzincation reaction can be combined in one pot with the Cu(I)-mediated electrophilic substitution of the C(sp2)-Zn bond to obtain synthetically challenging tetrasubstituted vinylgermanes.
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Affiliation(s)
| | - Fabrice Chemla
- Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, F-75005 Paris, France
| | - Franck Ferreira
- Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, F-75005 Paris, France
| | - Olivier Jackowski
- Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, F-75005 Paris, France
| | - Alejandro Perez-Luna
- Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, F-75005 Paris, France
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30
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Zachmann RJ, Fürstner A. Light-Driven gem Hydrogenation: An Orthogonal Entry into "Second-Generation" Ruthenium Carbene Catalysts for Olefin Metathesis. Chemistry 2021; 27:7663-7666. [PMID: 33871083 PMCID: PMC8251631 DOI: 10.1002/chem.202101176] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Indexed: 01/11/2023]
Abstract
The newly discovered light-driven gem hydrogenation of alkynes opens an unconventional yet efficient entry into five-coordinate Grubbs-type ruthenium carbene complexes with cis-disposed chloride ligands. Representatives of this class featuring a chelate substructure formed by an iodo-substituted benzylidene unit react with (substituted) 2-isopropoxystyrene to give prototypical "second-generation" Grubbs-Hoveyda complexes for olefin metathesis. The new approach to this venerable catalyst family is safe and versatile as it uses a triple bond rather than phenyldiazomethane as the ultimate carbene source and does not require any sacrificial phosphines.
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Affiliation(s)
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim/Ruhr, Germany
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31
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Nitrene-mediated intermolecular N-N coupling for efficient synthesis of hydrazides. Nat Chem 2021; 13:378-385. [PMID: 33753917 DOI: 10.1038/s41557-021-00650-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/01/2021] [Indexed: 01/31/2023]
Abstract
N-N linkages are found in many natural compounds and endow fascinating structural and functional properties. In comparison to the myriad methods for the construction of C-N bonds, chemistry for N-N coupling, especially in an intermolecular fashion, remains underdeveloped. Here, we report a nitrene-mediated intermolecular N-N coupling of dioxazolones and arylamines under iridium or iron catalysis. These reactions offer a simple and efficient method for the synthesis of various hydrazides from readily available carboxylic acid and amine precursors. Although the Ir-catalysed conditions usually give higher N-N coupling yield than the Fe-catalysed conditions, the reactions of sterically more demanding dioxazolones derived from α-substituted carboxylic acids work much better under the Fe-catalysed conditions. Mechanistic studies revealed that the nitrogen atom of Ir acyl nitrene intermediates has strong electrophilicity and can undergo nucleophilic attack with arylamines with the assistance of Cl···HN hydrogen bonding to form the N-N bond with high efficiency and chemoselectivity.
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32
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Herlé B, Späth G, Schreyer L, Fürstner A. Total Synthesis of Mycinolide IV and Path‐Scouting for Aldgamycin N. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202016475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Bart Herlé
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Georg Späth
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Lucas Schreyer
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
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33
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Späth G, Fürstner A. Scalable De Novo Synthesis of Aldgarose and Total Synthesis of Aldgamycin N. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202016477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Georg Späth
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
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34
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Herlé B, Späth G, Schreyer L, Fürstner A. Total Synthesis of Mycinolide IV and Path-Scouting for Aldgamycin N. Angew Chem Int Ed Engl 2021; 60:7893-7899. [PMID: 33448619 PMCID: PMC8048839 DOI: 10.1002/anie.202016475] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/13/2021] [Indexed: 12/19/2022]
Abstract
Proof-of-concept is provided that a large estate of 16-membered macrolide antibiotics can be reached by a "unified" approach. The key building block was formed on scale by an asymmetric vinylogous Mukaiyama aldol reaction; its alkene terminus was then converted either into the corresponding methyl ketone by Wacker oxidation or into a chain-extended aldehyde by catalyst-controlled branch-selective asymmetric hydroformylation. These transformations ultimately opened access to two structurally distinct series of macrolide targets. Notable late-stage maneuvers comprise a rare example of a ruthenium-catalyzed redox isomerization of an 1,3-enyne-5-ol into a 1,3-diene-5-one derivative, as well as the elaboration of a tertiary propargylic alcohol into an acyloin by trans-hydrostannation/Chan-Lam-type coupling. Moreover, this case study illustrates the underutilized possibility of forging complex macrolactone rings by transesterification under essentially neutral conditions.
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Affiliation(s)
- Bart Herlé
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Georg Späth
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Lucas Schreyer
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
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35
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Späth G, Fürstner A. Scalable De Novo Synthesis of Aldgarose and Total Synthesis of Aldgamycin N. Angew Chem Int Ed Engl 2021; 60:7900-7905. [PMID: 33448589 PMCID: PMC8048874 DOI: 10.1002/anie.202016477] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/13/2021] [Indexed: 12/25/2022]
Abstract
Since the accompanying study had shown that the introduction of the eponymous aldgarose sugar to the C5-OH group of the macrocyclic aglycone of aldgamycin N is most difficult, if not even impossible, the synthesis route was revised and the glycosidation performed at an earlier stage. To mitigate the "cost" of this strategic amendment, a practical and scalable de novo synthesis of this branched octose was developed. The glycoside formation required mild conditions; it commenced with the reaction of the aglycone with the trichloroacetimidate donor to give a transient orthoester, which slowly rearranged to the desired aldgaropyranoside. The presence of the polar peripheral groups in the product did not impede the selective late-stage functionalization of the macrolide ring itself: the contained propargylic alcohol entity was readily transformed into the characteristic acyloin motif of the target by a ruthenium-catalyzed trans-hydrostannation followed by a modified Chan-Lam-type coupling.
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Affiliation(s)
- Georg Späth
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
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36
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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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37
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Tracy JS, Kalnmals CA, Toste FD. Beyond Allylic Alkylation: Applications of Trost Chemistry in Complex Molecule Synthesis. Isr J Chem 2021. [DOI: 10.1002/ijch.202000103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Jacob S. Tracy
- Dept. of Chemistry University of California, Berkeley MC 1460 Berkeley CA 94720 USA
| | | | - F. Dean Toste
- Dept. of Chemistry University of California, Berkeley MC 1460 Berkeley CA 94720 USA
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38
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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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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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40
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Pounder A, Chen LD, Tam W. Ruthenium-Catalyzed [2 + 2] versus Homo Diels-Alder [2 + 2 + 2] Cycloadditions of Norbornadiene and Disubstituted Alkynes: A DFT Study. ACS OMEGA 2021; 6:900-911. [PMID: 33458541 PMCID: PMC7808161 DOI: 10.1021/acsomega.0c05499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
The ruthenium-catalyzed [2 + 2] and homo Diels-Alder [2 + 2 + 2] cycloadditions of norbornadiene with disubstituted alkynes are investigated using density functional theory (DFT). These DFT calculations provide a mechanistic explanation for observed reactivity trends with different functional groups. Alkynyl phosphonates and norbornadiene form the [2 + 2 + 2] cycloadduct, while other functionalized alkynes afford the respective [2 + 2] cycloadduct, in excellent agreement with experimental results. The computational studies on the potential energy profiles of the cycloadditions show that the rate-determining step for the [2 + 2] cycloaddition is the final reductive elimination step, but the overall rate for the [2 + 2 + 2] cycloaddition is controlled by the initial oxidative cyclization. Two distinct mechanistic pathways for the [2 + 2 + 2] cycloaddition, cationic and neutral, are characterized and reveal that Cp*RuCl(COD) energetically prefers the cationic pathway.
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41
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Kameo H, Mushiake A, Isasa T, Matsuzaka H, Bourissou D. Pd/Ni-Catalyzed Germa-Suzuki coupling via dual Ge–F bond activation. Chem Commun (Camb) 2021; 57:5004-5007. [DOI: 10.1039/d1cc01392k] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Pd/Ni → Ge–F interactions supported by phosphine-chelation were found to trigger dual activation of Ge–F bonds under mild conditions.
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Affiliation(s)
- Hajime Kameo
- Department of Chemistry
- Graduate School of Science
- Osaka Prefecture University
- Japan
| | - Akihiro Mushiake
- Department of Chemistry
- Graduate School of Science
- Osaka Prefecture University
- Japan
| | - Tomohito Isasa
- Department of Chemistry
- Graduate School of Science
- Osaka Prefecture University
- Japan
| | - Hiroyuki Matsuzaka
- Department of Chemistry
- Graduate School of Science
- Osaka Prefecture University
- Japan
| | - Didier Bourissou
- Laboratoire Hétérochimie Fondamentale et Appliquée
- Université Paul Sabatier/CNRS UMR 5069
- 31062 Toulouse Cedex 09
- France
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42
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Liu J, Song H, Wang T, Jia J, Tong QX, Tung CH, Wang W. Iron-Catalyzed Regiodivergent Hydrostannation of Alkynes: Intermediacy of Fe(IV)-H versus Fe(II)-Vinylidene. J Am Chem Soc 2020; 143:409-419. [PMID: 33371677 DOI: 10.1021/jacs.0c11448] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We report an iron system, Cp*Fe(1,2-R2PC6H4X), which controls the Markovnikov and anti-Markovnikov hydrostannation of alkynes by tuning the ionic metal-heteroatom bonds (Fe-X) reactivity. The sequential addition of nBu3SnH to the iron-amido catalyst (1, X = HN-, R = Ph) affords a distannyl Fe(IV)-H species responsible for syn-addition of the Sn-H bond across the C≡C bond to produce branched α-vinylstannanes. Activation of the C(sp)-H bond of alkynes by an iron-aryloxide catalyst (2, X = O-, R = Cy) affords an iron(II) vinylidene intermediate, allowing for gem-addition of the Sn-H to the terminal-carbon producing β-vinylstannanes. These catalytic reactions exhibit excellent regioselectivity and broad functional group compatibility and enable the large-scale synthesis of diverse vinylstannanes. Many new reactions have been established based on such a synthetic Fe-X platform to demonstrate that the initial step of the catalysis is conveniently controlled by the activation of either the tin hydride or the alkyne substrate.
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Affiliation(s)
- Jianguo Liu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Heng Song
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Tianlin Wang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Jiong Jia
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Qing-Xiao Tong
- Department of Chemistry, Shantou University, Shantou 515063, China
| | - Chen-Ho Tung
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Wenguang Wang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.,College of Chemistry, Beijing Normal University, Beijing 100875, China
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43
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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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44
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Ma J, Ding S. Transition Metal‐Catalyzed Cycloaddition of Azides with Internal Alkynes. ASIAN J ORG CHEM 2020. [DOI: 10.1002/ajoc.202000486] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Jiahao Ma
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering Beijing University of Chemical Technology North Third Ring Road 15 Beijing 100029 P. R. China
| | - Shengtao Ding
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering Beijing University of Chemical Technology North Third Ring Road 15 Beijing 100029 P. R. China
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45
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Barsu N, Leutzsch M, Fürstner A. Ruthenium-Catalyzed trans-Hydroalkynylation and trans-Chloroalkynylation of Internal Alkynes. J Am Chem Soc 2020; 142:18746-18752. [PMID: 33095568 PMCID: PMC7660751 DOI: 10.1021/jacs.0c08582] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
![]()
[Cp*RuCl]4 catalyzes the
addition of iPr3SiC≡CX (X = H,
Cl) across internal alkynes with
formation of 1,3-enyne or 1-chloro-1,3-enyne derivatives, respectively;
the reaction follows an unorthodox trans-addition
mode. The well-balanced affinities of the different reaction partners
to the ruthenium catalyst ensure that crossed addition prevails over
homodimerization of the individual components, as can be deduced from
spectroscopic and crystallographic data of various intermediates;
this includes a dinuclear complex in which an internal alkyne bridges
two [Cp*RuCl] fragments.
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Affiliation(s)
- Nagaraju Barsu
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
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46
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Peil S, Bistoni G, Goddard R, Fürstner A. Hydrogenative Metathesis of Enynes via Piano-Stool Ruthenium Carbene Complexes Formed by Alkyne gem-Hydrogenation. J Am Chem Soc 2020; 142:18541-18553. [PMID: 33073575 PMCID: PMC7596760 DOI: 10.1021/jacs.0c07808] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
![]()
The
only recently discovered gem-hydrogenation
of internal alkynes is a fundamentally new transformation, in which
both H atoms of dihydrogen are transferred to the same C atom of a
triple bond while the other position transforms into a discrete metal
carbene complex. [Cp*RuCl]4 is presently the catalyst of
choice: the resulting piano-stool ruthenium carbenes can engage a
tethered alkene into either cyclopropanation or metathesis, and a
prototypical example of such a reactive intermediate with an olefin
ligated to the ruthenium center has been isolated and characterized
by X-ray diffraction. It is the substitution pattern of the olefin
that determines whether metathesis or cyclopropanation takes place:
a systematic survey using alkenes of largely different character in
combination with a computational study of the mechanism at the local
coupled cluster level of theory allowed the preparative results to
be sorted and an intuitive model with predictive power to be proposed.
This model links the course of the reaction to the polarization of
the double bond as well as to the stability of the secondary carbene
complex formed, if metathesis were to take place. The first application
of “hydrogenative metathesis” to the total synthesis
of sinularones E and F concurred with this interpretation and allowed
the proposed structure of these marine natural products to be confirmed.
During this synthesis, it was found that gem-hydrogenation
also provides opportunities for C–H functionalization. Moreover,
silylated alkynes are shown to participate well in hydrogenative metathesis,
which opens a new entry into valuable allylsilane building blocks.
Crystallographic evidence suggests that the polarized [Ru–Cl]
bond of the catalyst interacts with the neighboring R3Si
group. Since attractive interligand Cl/R3Si contacts had
already previously been invoked to explain the outcome of various
ruthenium-catalyzed reactions, including trans-hydrosilylation,
the experimental confirmation provided herein has implications beyond
the present case.
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Affiliation(s)
- Sebastian Peil
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Giovanni Bistoni
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany
| | - Richard Goddard
- 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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Biberger T, Zachmann RJ, Fürstner A. Grubbs Metathesis Enabled by a Light-Driven gem-Hydrogenation of Internal Alkynes. Angew Chem Int Ed Engl 2020; 59:18423-18429. [PMID: 32608043 PMCID: PMC7589215 DOI: 10.1002/anie.202007030] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/19/2020] [Indexed: 02/02/2023]
Abstract
[(NHC)(cymene)RuCl2 ] (NHC=N-heterocyclic carbene) complexes instigate a light-driven gem-hydrogenation of internal alkynes with concomitant formation of discrete Grubbs-type ruthenium carbene species. This unorthodox reactivity mode is harnessed in the form of a "hydrogenative metathesis" reaction, which converts an enyne substrate into a cyclic alkene. The intervention of ruthenium carbenes formed in the actual gem-hydrogenation step was proven by the isolation and crystallographic characterization of a rather unusual representative of this series carrying an unconfined alkyl group on a disubstituted carbene center.
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Affiliation(s)
- Tobias Biberger
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | | | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
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48
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Biberger T, Zachmann RJ, Fürstner A. Grubbs Metathesis Enabled by a Light‐Driven
gem
‐Hydrogenation of Internal Alkynes. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202007030] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Tobias Biberger
- 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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Jin H, Fürstner A. Modular Synthesis of Furans with up to Four Different Substituents by a trans-Carboboration Strategy. Angew Chem Int Ed Engl 2020; 59:13618-13622. [PMID: 32374441 PMCID: PMC7496670 DOI: 10.1002/anie.202005560] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Indexed: 01/18/2023]
Abstract
Propargyl alcohols, on treatment with MHMDS (M=Na, K), B2 (pin)2 , an acid chloride and a palladium/copper co-catalyst system, undergo a reaction cascade comprised of trans-diboration, regioselective acylation, cyclization and dehydration to give trisubstituted furylboronic acid pinacol ester derivatives in good yields; subsequent Suzuki coupling allows a fourth substituent of choice to be introduced and hence tetrasubstituted (arylated) furans to be formed. In terms of modularity, the method seems unrivaled, not least because each product can be attained by two orthogonal but convergent ways ("diagonal split"). This asset is illustrated by the "serial" formation of a "library" of all twelve possible furan isomers that result from systematic permutation of four different substituents about the heterocyclic core.
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Affiliation(s)
- Hongming Jin
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim/Ruhr, Germany
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50
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Jin H, Fürstner A. Modular Synthesis of Furans with up to Four Different Substituents by a
trans
‐Carboboration Strategy. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202005560] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Hongming Jin
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung 45470 Mülheim/Ruhr Germany
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