1
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Suresh R, Orbach N, Marek I. Stereoinvertive S N1 Through Neighboring Group Participation. Angew Chem Int Ed Engl 2024:e202407602. [PMID: 38763909 DOI: 10.1002/anie.202407602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/16/2024] [Accepted: 05/17/2024] [Indexed: 05/21/2024]
Abstract
Neighboring group participation, the assistance of non-conjugated electrons to a reaction center, is a fundamental phenomenon in chemistry. In the framework of nucleophilic substitution reactions, neighboring group participation is known to cause rate acceleration, first order kinetics (SN1), and retention of configuration. The latter phenomenon is a result of double inversion: the first one when the neighboring group displaces the leaving group, and the second when a nucleophile substitutes the neighboring group. This powerful control of stereoretention has been widely used in organic synthesis for more than a century. However, neighboring group participation may also lead to inversion of configuration, a phenomenon which is often overlooked. Herein, we review this unique mode of stereoinversion, dividing the relevant reactions into three classes with the aim to introduce a fresh perspective on the different modes of stereoinversion via neighboring group participation as well as the factors that control this stereochemical outcome.
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Affiliation(s)
- Rahul Suresh
- Schulich Faculty of Chemistry and the Resnick Sustainability Center for Catalysis, Technion - Israel Institute of Technology, Technion City, Haifa, 3200009, Israel
| | - Noam Orbach
- Schulich Faculty of Chemistry and the Resnick Sustainability Center for Catalysis, Technion - Israel Institute of Technology, Technion City, Haifa, 3200009, Israel
| | - Ilan Marek
- Schulich Faculty of Chemistry and the Resnick Sustainability Center for Catalysis, Technion - Israel Institute of Technology, Technion City, Haifa, 3200009, Israel
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2
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Myronova V, Cahard D, Marek I. Stereoselective Nucleophilic Halogenation at CF 3-Substituted Nonclassical Carbocation. Org Lett 2024; 26:3657-3660. [PMID: 38657180 DOI: 10.1021/acs.orglett.4c01161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
CF3-substituted cyclopropyl carbinol derivatives undergo regioselective and diastereoselective nucleophilic halogenation at the quaternary carbon center to provide acyclic products as a single diastereomer. The selectivity of the substitution is rationalized by the formation of a nonclassical cyclopropylcarbinyl cation intermediate, reacting at the most-substituted carbon center. Tertiary alkyl chlorides, bromides, and fluorides adjacent to a stereogenic C-CF3-motif are diastereomerically pure and can be obtained in few catalytic steps from commercially available alkynes.
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Affiliation(s)
- Veronika Myronova
- The Mallat Family Laboratory of Organic Chemistry, Schulich Faculty of Chemistry and the Resnick Sustainability Center for Catalysis. Technion-Israel Institute of Technology, Haifa 3200009, Israel
- CNRS, UMR 6014 COBRA, Univ Rouen Normandie, INSA Rouen Normandie, Normandie Univ, INC3M FR 3038, F-76000 Rouen, France
| | - Dominique Cahard
- CNRS, UMR 6014 COBRA, Univ Rouen Normandie, INSA Rouen Normandie, Normandie Univ, INC3M FR 3038, F-76000 Rouen, France
| | - Ilan Marek
- The Mallat Family Laboratory of Organic Chemistry, Schulich Faculty of Chemistry and the Resnick Sustainability Center for Catalysis. Technion-Israel Institute of Technology, Haifa 3200009, Israel
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3
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Galeotti M, Bietti M, Costas M. Catalyst and Medium Control over Rebound Pathways in Manganese-Catalyzed Methylenic C-H Bond Oxidation. J Am Chem Soc 2024; 146:8904-8914. [PMID: 38506665 PMCID: PMC10996012 DOI: 10.1021/jacs.3c11555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 03/21/2024]
Abstract
The C(sp3)-H bond oxygenation of a variety of cyclopropane containing hydrocarbons with hydrogen peroxide catalyzed by manganese complexes containing aminopyridine tetradentate ligands was carried out. Oxidations were performed in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) and 2,2,2-trifluoroethanol (TFE) using different manganese catalysts and carboxylic acid co-ligands, where steric and electronic properties were systematically modified. Functionalization selectively occurs at the most activated C-H bonds that are α- to cyclopropane, providing access to carboxylate or 2,2,2-trifluoroethanolate transfer products, with no competition, in favorable cases, from the generally dominant hydroxylation reaction. The formation of mixtures of unrearranged and rearranged esters (oxidation in HFIP in the presence of a carboxylic acid) and ethers (oxidation in TFE) with full control over diastereoselectivity was observed, confirming the involvement of delocalized cationic intermediates in these transformations. Despite such a complex mechanistic scenario, by fine-tuning of catalyst and carboxylic acid sterics and electronics and leveraging on the relative contribution of cationic pathways to the reaction mechanism, control over product chemoselectivity could be systematically achieved. Taken together, the results reported herein provide powerful catalytic tools to rationally manipulate ligand transfer pathways in C-H oxidations of cyclopropane containing hydrocarbons, delivering novel products in good yields and, in some cases, outstanding selectivities, expanding the available toolbox for the development of synthetically useful C-H functionalization procedures.
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Affiliation(s)
- Marco Galeotti
- QBIS
Research Group, Institut de Química Computacional i Catàlisi
(IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia, Spain
| | - Massimo Bietti
- Dipartimento
di Scienze e Tecnologie Chimiche, Università
“Tor Vergata”, Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
| | - Miquel Costas
- QBIS
Research Group, Institut de Química Computacional i Catàlisi
(IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona E-17071, Catalonia, Spain
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4
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Patel K, Oginetz L, Marek I. Highly Diastereoselective Preparation of Tertiary Alkyl Thiocyanates en Route to Thiols by Stereoinvertive Nucleophilic Substitution at Nonclassical Carbocations. Org Lett 2023; 25:8474-8477. [PMID: 37982581 DOI: 10.1021/acs.orglett.3c03396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2023]
Abstract
An effective InBr3-catalyzed nucleophilic thiocyanation of cyclopropyl alcohols has been developed. The reaction takes place at the quaternary carbon stereocenter of the cyclopropyl carbinol with a complete inversion of configuration, offering a novel pathway for the creation of complex tertiary alkyl thiocyanates with high diastereopurity. These substitution reactions proceed under mild reaction conditions and tolerate several functional groups. Additionally, thiocyanates were converted to thiols using lithium aluminum hydride.
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Affiliation(s)
- Kaushalendra Patel
- Schulich Faculty of Chemistry and Resnick Sustainability Center for Catalysis, Technion - Israel Institute of Technology, Technion City, Haifa 3200009, Israel
| | - Lior Oginetz
- Schulich Faculty of Chemistry and Resnick Sustainability Center for Catalysis, Technion - Israel Institute of Technology, Technion City, Haifa 3200009, Israel
| | - Ilan Marek
- Schulich Faculty of Chemistry and Resnick Sustainability Center for Catalysis, Technion - Israel Institute of Technology, Technion City, Haifa 3200009, Israel
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5
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Salin AV, Shabanov AA, Khayarov KR, Nugmanov RI, Islamov DR. Stereoelectronic Effect in the Reaction of α-Methylene Lactones with Tertiary Phosphines and Its Application in Organocatalysis. J Org Chem 2023; 88:11954-11967. [PMID: 37540578 DOI: 10.1021/acs.joc.3c01223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/06/2023]
Abstract
The kinetic data indicate that the addition of tertiary phosphines to α-methylene lactones in acetic acid is strongly accelerated in comparison to the reactions of related open-chain esters. Six-membered α-methylene-δ-valerolactone exhibited a more pronounced rate increase than five-membered α-methylene-γ-butyrolactone. The use of α-methylene-γ-butyrolactam as a nitrogen analogue of α-methylene-γ-butyrolactone resulted in a total loss of the reaction acceleration. The observed reactivities were rationalized by DFT calculations at the RwB97XD/6-31+G(d,p) level of theory, showing that the intramolecular interaction between phosphonium and enolate oxygen centers provided by the locked s-cis-geometry of the heterocycles plays an important role in the stabilization of intermediate zwitterions. The reactivity is also controlled by the conformational flexibility of the heterocycle. The geometries of five-membered and, especially, six-membered lactone cycles are slightly changed upon the nucleophilic attack of phosphine, leading to the stabilizing stereoelectronic effect by the Ρ···Ο interaction. The addition of phosphine to α-methylene-γ-butyrolactam significantly distorts the initial geometry of the heterocycle, making the nucleophilic attack unfavorable. The application of the stereoelectronic effect to enhance the efficiency of the phosphine-catalyzed Michael and Pudovik reactions of α-methylene lactones was demonstrated.
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Affiliation(s)
- Alexey V Salin
- A.M. Butlerov Institute of Chemistry,Kazan Federal University, Kremlevskaya Street 18, Kazan 420008, Russian Federation
| | - Andrey A Shabanov
- A.M. Butlerov Institute of Chemistry,Kazan Federal University, Kremlevskaya Street 18, Kazan 420008, Russian Federation
| | - Khasan R Khayarov
- A.M. Butlerov Institute of Chemistry,Kazan Federal University, Kremlevskaya Street 18, Kazan 420008, Russian Federation
| | - Ramil I Nugmanov
- Janssen Research & Development, Janssen Pharmaceutica N.V., Turnhoutseweg 30, Beerse B-2340, Belgium
| | - Daut R Islamov
- Laboratory for Structural Analysis of Biomacromolecules, Kazan Scientific Center of Russian Academy of Science, Kremlevskaya Street 31, Kazan 420008, Russian Federation
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6
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Li QH, Zhang GS, Wang F, Cen Y, Liu XL, Zhang JW, Wang YH, Lee AWM, Gao D, Lin GQ, Tian P. Nature-inspired catalytic asymmetric rearrangement of cyclopropylcarbinyl cation. SCIENCE ADVANCES 2023; 9:eadg1237. [PMID: 37163601 PMCID: PMC10171815 DOI: 10.1126/sciadv.adg1237] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
In nature, cyclopropylcarbinyl cation is often involved in cationic cascade reactions catalyzed by natural enzymes to produce a great number of structurally diverse natural substances. However, mimicking this natural process with artificial organic catalysts remains a daunting challenge in synthetic chemistry. We report a small molecule-catalyzed asymmetric rearrangement of cyclopropylcarbinyl cations, leading to a series of chiral homoallylic sulfide products with good to excellent yields and enantioselectivities (up to 99% enantiomeric excess). In the presence of a chiral SPINOL-derived N-triflyl phosphoramide catalyst, the dehydration of prochiral cyclopropylcarbinols occurs rapidly to generate symmetrical cyclopropylcarbinyl cations, which are subsequently trapped by thione-containing nucleophiles. A subgram-scale experiment and multiple downstream transformations of the sulfide products are further pursued to demonstrate the synthetic utility. Notably, a few heteroaromatic sulfone derivatives could serve as "covalent warhead" in the enzymatic inhibition of severe acute respiratory syndrome coronavirus 2 main protease.
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Affiliation(s)
- Qing-Hua Li
- The Research Center of Chiral Drugs, Shanghai Frontiers Science Center of TCM Chemical Biology, Innovation Research Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai 201203, China
| | - Gui-Shan Zhang
- The Research Center of Chiral Drugs, Shanghai Frontiers Science Center of TCM Chemical Biology, Innovation Research Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai 201203, China
| | - Feng Wang
- The Research Center of Chiral Drugs, Shanghai Frontiers Science Center of TCM Chemical Biology, Innovation Research Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai 201203, China
| | - Yixin Cen
- The Research Center of Chiral Drugs, Shanghai Frontiers Science Center of TCM Chemical Biology, Innovation Research Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai 201203, China
| | - Xi-Liang Liu
- The Research Center of Chiral Drugs, Shanghai Frontiers Science Center of TCM Chemical Biology, Innovation Research Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai 201203, China
| | - Jian-Wei Zhang
- The Research Center of Chiral Drugs, Shanghai Frontiers Science Center of TCM Chemical Biology, Innovation Research Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai 201203, China
| | - Yu-Hui Wang
- The Research Center of Chiral Drugs, Shanghai Frontiers Science Center of TCM Chemical Biology, Innovation Research Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai 201203, China
| | - Albert W M Lee
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Dingding Gao
- The Research Center of Chiral Drugs, Shanghai Frontiers Science Center of TCM Chemical Biology, Innovation Research Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai 201203, China
| | - Guo-Qiang Lin
- The Research Center of Chiral Drugs, Shanghai Frontiers Science Center of TCM Chemical Biology, Innovation Research Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai 201203, China
| | - Ping Tian
- The Research Center of Chiral Drugs, Shanghai Frontiers Science Center of TCM Chemical Biology, Innovation Research Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai 201203, China
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7
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Larmore SP, Champagne PA. Cyclopropylcarbinyl-to-Homoallyl Carbocation Equilibria Influence the Stereospecificity in the Nucleophilic Substitution of Cyclopropylcarbinols. J Org Chem 2023. [PMID: 37141426 DOI: 10.1021/acs.joc.3c00257] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The synthesis of quaternary homoallylic halides and trichloroacetates from cyclopropylcarbinols, as reported by Marek (J. Am. Chem. Soc. 2020, 142, 5543-5548), is one of the few reported examples of stereospecific nucleophilic substitution involving chiral bridged carbocations. However, for the phenyl-substituted substrates, poor specificity is observed and mixtures of diastereomers are obtained. To understand the nature of the intermediates involved and explain the loss of specificity for certain substrates, we have performed a computational investigation of the reaction mechanism using ωB97X-D optimizations and DLPNO-CCSD(T) energy refinements. Our results indicate that cyclopropylcarbinyl cations are stable intermediates in this reaction, while bicyclobutonium structures are high-energy transition structures that are not involved. Instead, multiple rearrangement pathways of cyclopropylcarbinyl cations were located, including ring openings to homoallylic cations. The activation barriers required to reach such structures are correlated to the nature of the substituents; while direct nucleophilic attack on the chiral cyclopropylcarbinyl cations is kinetically favored for most systems, the rearrangements become competitive with nucleophilic attack for the phenyl-substituted systems, leading to a loss of specificity through rearranged carbocation intermediates. As such, stereospecific reactions of chiral cyclopropylcarbinyl cations depend on the energies required to access their corresponding homoallylic structures, from which selectivity is not guaranteed.
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Affiliation(s)
- Sean P Larmore
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States
| | - Pier Alexandre Champagne
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States
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8
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Biswas K, Khamrai A, Malik S, Ganesh V. Organophosphorus-Catalyzed Borylative Ring-Opening of Vinylcyclopropanes: A Stereoselective Route to δ-Valerolactones. Org Lett 2023; 25:1805-1810. [PMID: 36919935 DOI: 10.1021/acs.orglett.2c04284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
We report an operationally simple route to δ-valerolactones through an organophosphorus-catalyzed borylative ring-opening/allylation of vinylcyclopropanes providing δ-hydroxy esters stereoselectively. The δ-hydroxy esters were lactonized to obtain densely substituted δ-valerolactones. The present methodology exhibited enhanced functional group tolerance compared to the existing metal-mediated methods. A plausible mechanism for borylative ring-opening reaction has been suggested. 31P NMR studies indicated the involvement of a phosphonium zwitterionic species. The synthetic utility of the intermediate allyl boronates was demonstrated.
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Affiliation(s)
- Krishna Biswas
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal-721302, India
| | - Aankhi Khamrai
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal-721302, India
| | - Subrata Malik
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal-721302, India
| | - Venkataraman Ganesh
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal-721302, India
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9
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Jung M, Muir JE, Lindsay VNG. Expedient synthesis of spiro[3.3]heptan-1-ones via strain-relocating semipinacol rearrangements. Tetrahedron 2023; 134:133296. [PMID: 36937489 PMCID: PMC10019042 DOI: 10.1016/j.tet.2023.133296] [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] [Indexed: 02/05/2023]
Abstract
A novel approach for the formation of the highly strained spiro[3.3]heptan-1-one motif was developed through the reaction of 1-sulfonylcyclopropanols and lithiated 1-sulfonylbicyclo[1.1.0]butanes. Following initial nucleophilic addition to the cyclopropanone formed in situ, the resulting 1-bicyclobutylcyclopropanol intermediate is prone to a 'strain-relocating' semipinacol rearrangement in the presence of acid, directly affording the substituted spiro[3.3]heptan-1-one. The process is shown to be fully regio- and stereospecific when starting from a substituted cyclopropanone equivalent, leading to optically active 3-substituted spiro[3.3]heptan-1-ones. The reaction likely proceeds via initial protonation of the bicyclobutyl moiety followed by [1,2]-rearrangement of the resulting cyclopropylcarbinyl cation.
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Affiliation(s)
- Myunggi Jung
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, North Carolina 27695, United States
| | - Joanna E Muir
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, North Carolina 27695, United States
| | - Vincent N G Lindsay
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, North Carolina 27695, United States
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10
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Chen X, Patel K, Marek I. Stereoselective Construction of Tertiary Homoallyl Alcohols and Ethers by Nucleophilic Substitution at Quaternary Carbon Stereocenters. Angew Chem Int Ed Engl 2023; 62:e202212425. [PMID: 36413111 PMCID: PMC10107121 DOI: 10.1002/anie.202212425] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/13/2022] [Accepted: 11/22/2022] [Indexed: 11/24/2022]
Abstract
An efficient method for the stereoselective construction of tertiary C-O bonds via a stereoinvertive nucleophilic substitution at the quaternary carbon stereocenter of cyclopropyl carbinol derivatives using water, alcohols and phenols as nucleophiles has been developed. This substitution reaction proceeds under mild conditions and tolerates several functional groups, providing a new access to the stereoselective formation of highly congested tertiary homoallyl alcohols and ethers.
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Affiliation(s)
- Xu Chen
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology Technion City, Haifa, 3200009, Israel
| | - Kaushalendra Patel
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology Technion City, Haifa, 3200009, Israel
| | - Ilan Marek
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology Technion City, Haifa, 3200009, Israel
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11
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Chen X, Patel K, Marek I. Stereospecific nucleophilic substitution at quaternary carbon stereocenters of cyclopropyl carbinols. Chem 2023. [DOI: 10.1016/j.chempr.2023.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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12
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Xie J, Dong G. Cyclopropylcarbinyl cation chemistry in synthetic method development and natural product synthesis: cyclopropane formation and skeletal rearrangement. Org Chem Front 2023. [DOI: 10.1039/d3qo00282a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
In this Review, the underrecognized utilities of the cyclopropylcarbinyl cation chemistry are summarized in cyclopropane synthesis and skeletal rearrangements, and their applications in natural product total synthesis are highlighted.
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13
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Pavlíčková T, Stöckl Y, Marek I. Synthesis and Functionalization of Tertiary Propargylic Boronic Esters by Alkynyllithium-Mediated 1,2-Metalate Rearrangement of Borylated Cyclopropanes. Org Lett 2022; 24:8901-8906. [PMID: 36446049 PMCID: PMC9791689 DOI: 10.1021/acs.orglett.2c03756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Implementing the use of alkynyllithium reagents in a stereospecific 1,2-metalate rearrangement-mediated ring opening of polysubstituted cyclopropyl boronic esters provides a variety of tertiary pinacol boranes bearing adjacent tertiary or quaternary carbon stereocenters with high levels of diastereomeric purity. The potential of this strategy was demonstrated through a selection of α- and γ-functionalization of the propargyl boronic esters.
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14
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Bai H, Han L, Wang X, Yan H, Leng H, Chen S, Ma H. Anion Migrated Ring Opening and Rearrangement in Anionic Polymerization Induced C7 and C8 Polymerizations. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c01233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hongyuan Bai
- Department of Polymer Science and Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Li Han
- Department of Polymer Science and Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Xuefei Wang
- Department of Polymer Science and Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Hong Yan
- Department of Polymer Science and Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Haitao Leng
- Department of Polymer Science and Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Siwei Chen
- Department of Polymer Science and Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Hongwei Ma
- Department of Polymer Science and Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
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15
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Augustin AU, Di Silvio S, Marek I. Borylated Cyclopropanes as Spring-Loaded Entities: Access to Vicinal Tertiary and Quaternary Carbon Stereocenters in Acyclic Systems. J Am Chem Soc 2022; 144:16298-16302. [PMID: 36041738 PMCID: PMC9479080 DOI: 10.1021/jacs.2c07394] [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] [Indexed: 11/30/2022]
Abstract
![]()
Herein, we present the formation of acyclic frameworks
bearing
two consecutive stereocenters of either tertiary or quaternary nature
starting from easily accessible cyclopropenes. This holistic approach
involves a regio- and diastereoselective hydro- or carboborylation
of substituted cyclopropenyl esters. Formation of boronate complexes
of the latter via the addition of nucleophiles and subsequent stereospecific
1,2-migration with carbon–carbon bond cleavage delivered the
title compounds.
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Affiliation(s)
- André U Augustin
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 3200009, Israel
| | - Sergio Di Silvio
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 3200009, Israel
| | - Ilan Marek
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 3200009, Israel
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