1
|
Darzina M, Jirgensons A. Electrochemical Formation of Oxazolines by 1,3-Oxyfluorination of Non-activated Cyclopropanes. Org Lett 2024; 26:2158-2162. [PMID: 38456832 DOI: 10.1021/acs.orglett.4c00143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
The C-C bond in non-activated cyclopropanes can be intramolecularly cleaved with an electrochemically generated amidyl radical forming oxazolines. In the presence of TBABF4, this provides 1,3-oxyfluorination products. C-C bond cleavage of cyclopropane proceeds with inversion of the configuration, suggesting an intramolecular homolytic substitution (SHi) mechanism. The performance of TBABF4 as an efficient fluoride source was explained by accumulation of the BF4- anion at the anode surface, at which a carbocation is formed by the oxidation of the C-centered radical.
Collapse
Affiliation(s)
- Madara Darzina
- Latvian Institute of Organic Synthesis, Aizkraukles 21, LV-1006 Riga, Latvia
| | - Aigars Jirgensons
- Latvian Institute of Organic Synthesis, Aizkraukles 21, LV-1006 Riga, Latvia
| |
Collapse
|
2
|
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.
Collapse
|
3
|
Abstract
The various facets of the chemistry of cyclopropane derivatives, the smallest carbocycle, are amazingly diverse and continue to fascinate theoreticians, synthetic or structural chemists having interest in fundamental physical, medicinal chemistry, and natural product synthesis. The challenges generated by this intriguing cyclic arrangement of only three tetravalent carbons represent a wide area of the chemical spectrum. From fundamental aspects of bonding through the synthesis of highly strained molecules, the understanding of the mode of action in biological systems to the selective cleavage into acyclic substrates makes the chemistry of these small rings fascinating. Therefore, efficient routes to prepare differently polysubstituted cyclopropanes have always been of a primordial importance. In the past decade, we and others have expanded the scope of the carbometalation reaction of cyclopropenes as a broad and general method to the formation of stereodefined cyclopropane derivatives. Although cyclopropenes, with their even higher strain energy, easily undergo addition reactions of organometallic reagents, their carbometalation reactions generate new regio-, diastereo-, and enantioselectivity issues that needed to be addressed. These various stereochemical aspects accompanied our research from its origins to today, and we are proposing in this Account, a didactic overview of the different ways by which cyclopropenes can lead to the formation of polysubstituted cyclopropanes or open-products possessing several stereogenic centers as a single regio- and diastereomer.We initially launched our research campaign on the chemistry of these strained three-membered rings by the regio- and diastereoselective copper-catalyzed carbomagnesiation of enantiomerically enriched cyclopropenyl carbinols. The directing alcohol governed both the regio- and diastereoselectivity of the addition and also served as a good leaving group as it undergoes a selective 1,2-elimination reaction to provide enantioenriched alkylidenecyclopropanes in excellent yields and enantiomeric excesses. Then, we turned our attention to the regio- and stereoselective synthesis of stereodefined tri- and tetrasubstituted cyclopropanes through the diastereoselective addition to sp2- monosubstituted cyclopropenyl ester derivatives. With the aim to further expand this concept to the formation of penta- and hexa-substituted cyclopropanes as single isomer, we had first to design the preparation of the required 1,2-disubstituted cyclopropenes that would control the regioselective addition of the organometallic derivatives. The synthesis of penta- and hexa-substituted cyclopropanes was then reported for the first time as a single regio- and diastereomer. It should be noted that the in situ formed cyclopropyl-metal intermediate is configurationally stable and can be subsequently functionalized with pure retention of the configuration by addition of electrophiles. Then, the enantioselective-catalyzed carbometalation reaction of achiral cyclopropenes allowed the synthesis of several new classes of cyclopropane derivatives in high enantiomeric ratios. Finally, by combining the regio- and diastereoselective carbometalation reaction of a cyclopropene with a subsequent reaction of the resulting cyclopropylmetal species, a selective carbon-carbon bond cleavage was observed to lead to the preparation of acyclic substrates possessing several stereocenters including a quaternary carbon stereogenic center. Our original vision of using strain within an embedded double bond in a three-membered ring has provided new routes to the stereoselective synthesis of polysubstituted cyclopropanes and has been extremely successful, as it represents a current new tool for the synthesis of persubstituted cyclopropanes as a single diastereomer.
Collapse
|
4
|
Siddaraju Y, Sabbatani J, Cohen A, Marek I. Preparation of Distant Quaternary Carbon Stereocenters by Double Selective Ring-Opening of 1,1-Biscyclopropyl Methanol Derivatives. Angew Chem Int Ed Engl 2022; 61:e202203652. [PMID: 35521738 PMCID: PMC9401570 DOI: 10.1002/anie.202203652] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Indexed: 12/15/2022]
Abstract
The diastereoselective double carbometalation reaction of cyclopropenes provides, in a single‐pot operation, two ω‐ene‐[1,1]‐bicyclopropyl ester derivatives. One regioisomer then undergoes a Pd‐catalyzed addition of aryl iodide to provide skipped dienes possessing several distant stereocenters including two congested quaternary carbon centers with excellent diastereoselectivity.
Collapse
Affiliation(s)
- Yogesh Siddaraju
- Schulich Faculty of Chemistry, Technion-, Israel Institute of Technology, Technion City, 3200009, Haifa, Israel
| | - Juliette Sabbatani
- Schulich Faculty of Chemistry, Technion-, Israel Institute of Technology, Technion City, 3200009, Haifa, Israel
| | - Anthony Cohen
- Schulich Faculty of Chemistry, Technion-, Israel Institute of Technology, Technion City, 3200009, Haifa, Israel
| | - Ilan Marek
- Schulich Faculty of Chemistry, Technion-, Israel Institute of Technology, Technion City, 3200009, Haifa, Israel
| |
Collapse
|
5
|
Wang Z, Gao P, Lin E, Li B. Stereodefined Skipped Dienes through Iridium‐Catalyzed Formal Addition of Tertiary Allylic C−H Bonds to Alkynes. Angew Chem Int Ed Engl 2022; 61:e202200075. [DOI: 10.1002/anie.202200075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Indexed: 11/08/2022]
Affiliation(s)
- Zi‐Xuan Wang
- Center of Basic Molecular Science (CBMS) Department of Chemistry Tsinghua University Beijing 100084 China
| | - Peng‐Chao Gao
- Center of Basic Molecular Science (CBMS) Department of Chemistry Tsinghua University Beijing 100084 China
| | - En‐Ze Lin
- Center of Basic Molecular Science (CBMS) Department of Chemistry Tsinghua University Beijing 100084 China
| | - Bi‐Jie Li
- Center of Basic Molecular Science (CBMS) Department of Chemistry Tsinghua University Beijing 100084 China
- Beijing National Laboratory for Molecular Sciences Beijing 100190 China
- Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192 China
| |
Collapse
|
6
|
Siddaraju Y, Sabbatani J, Cohen A, Marek I. Preparation of Distant Quaternary Carbon Stereocenters by Double Selective Ring‐Opening of 1,1‐Biscyclopropyl Methanol Derivatives. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202203652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Anthony Cohen
- Technion Israel Institute of Technology Chemistry ISRAEL
| | - Ilan Marek
- Technion - Israel Institute of Technology Schulich Faculty of Chemistry Technion City 32000 Haifa ISRAEL
| |
Collapse
|
7
|
Wang Z, Gao P, Lin E, Li B. Stereodefined Skipped Dienes through Iridium‐Catalyzed Formal Addition of Tertiary Allylic C−H Bonds to Alkynes. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202200075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Zi‐Xuan Wang
- Center of Basic Molecular Science (CBMS) Department of Chemistry Tsinghua University Beijing 100084 China
| | - Peng‐Chao Gao
- Center of Basic Molecular Science (CBMS) Department of Chemistry Tsinghua University Beijing 100084 China
| | - En‐Ze Lin
- Center of Basic Molecular Science (CBMS) Department of Chemistry Tsinghua University Beijing 100084 China
| | - Bi‐Jie Li
- Center of Basic Molecular Science (CBMS) Department of Chemistry Tsinghua University Beijing 100084 China
- Beijing National Laboratory for Molecular Sciences Beijing 100190 China
- Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192 China
| |
Collapse
|
8
|
Patel K, Lanke V, Marek I. Stereospecific Construction of Quaternary Carbon Stereocenters from Quaternary Carbon Stereocenters. J Am Chem Soc 2022; 144:7066-7071. [PMID: 35412821 PMCID: PMC9052742 DOI: 10.1021/jacs.2c01695] [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: 11/30/2022]
Abstract
![]()
Organoaluminum species
promote a smooth nucleophilic substitution
at the quaternary carbon stereocenter of stereodefined polysubstituted
cyclopropyl methyl phosphate with a complete inversion of configuration,
even when more reactive functional groups are present. The regio-
and diastereoselectivity of the substitution is attributed to the
existence of a bicyclobutonium intermediate.
Collapse
Affiliation(s)
- Kaushalendra Patel
- The Mallat Family Laboratory of Organic Chemistry, Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Veeranjaneyulu Lanke
- The Mallat Family Laboratory of Organic Chemistry, Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Ilan Marek
- The Mallat Family Laboratory of Organic Chemistry, Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel
| |
Collapse
|
9
|
Cohen A, Kaushansky A, Marek I. Mechanistic Insights on the Selectivity of the Tandem Heck-Ring-Opening of Cyclopropyldiol Derivatives. JACS AU 2022; 2:687-696. [PMID: 35373195 PMCID: PMC8970019 DOI: 10.1021/jacsau.1c00547] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Indexed: 06/14/2023]
Abstract
The preparation of a new class of alkenyl cyclopropyl diols, easily available through a copper-catalyzed carbometalation reaction of cyclopropenes, has enabled the study of key mechanistic aspects of the tandem Heck-cyclopropane ring-opening reaction. Utilizing these substrates containing two distinct hydroxyl groups allowed us to examine parameters affecting the reaction outcome and selectivity. The combination of these experimental results with detailed DFT studies shed light on the mechanism governing the regio- and stereoselectivity of the cyclopropane ring-opening. A thorough investigation displayed the dual roles fulfilled by the hydroxyl group during the reaction, which is key to this remarkable transformation. In addition to its mechanistic implication, the reaction granted access to various lactones possessing up to four stereocenters as a single diastereomer, conveniently prepared in only two catalytic steps from easily accessible achiral cyclopropenes.
Collapse
|
10
|
Cohen Y, Augustin AU, Levy L, Jones PG, Werz DB, Marek I. Regio- and Diastereoselective Copper-Catalyzed Carbomagnesiation for the Synthesis of Penta- and Hexa-Substituted Cyclopropanes. Angew Chem Int Ed Engl 2021; 60:11804-11808. [PMID: 33742749 DOI: 10.1002/anie.202102509] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Indexed: 11/07/2022]
Abstract
Despite the highly strained nature of cyclopropanes possessing three vicinal quaternary carbon stereocenters, the regio- and diastereoselective copper-catalyzed carbomagnesiation reaction of cyclopropenes provides an easy and efficient access to these novel persubstituted cyclopropyl cores with a complete regio- and diastereoselectivity.
Collapse
Affiliation(s)
- Yair Cohen
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa, 3200009, Israel
| | - André U Augustin
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa, 3200009, Israel
| | - Laura Levy
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa, 3200009, Israel
| | - Peter G Jones
- Technische Universität Braunschweig, Institute of Inorganic and Analytical Chemistry, Hagenring 30, 38106, Braunschweig, Germany
| | - Daniel B Werz
- Technische Universität Braunschweig, Institute of Organic Chemistry, Hagenring 30, 38106, Braunschweig, Germany
| | - Ilan Marek
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa, 3200009, Israel
| |
Collapse
|
11
|
Cohen Y, Augustin AU, Levy L, Jones PG, Werz DB, Marek I. Regio‐ and Diastereoselective Copper‐Catalyzed Carbomagnesiation for the Synthesis of Penta‐ and Hexa‐Substituted Cyclopropanes. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102509] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Yair Cohen
- Schulich Faculty of Chemistry Technion—Israel Institute of Technology Technion City Haifa 3200009 Israel
| | - André U. Augustin
- Schulich Faculty of Chemistry Technion—Israel Institute of Technology Technion City Haifa 3200009 Israel
| | - Laura Levy
- Schulich Faculty of Chemistry Technion—Israel Institute of Technology Technion City Haifa 3200009 Israel
| | - Peter G. Jones
- Technische Universität Braunschweig Institute of Inorganic and Analytical Chemistry Hagenring 30 38106 Braunschweig Germany
| | - Daniel B. Werz
- Technische Universität Braunschweig Institute of Organic Chemistry Hagenring 30 38106 Braunschweig Germany
| | - Ilan Marek
- Schulich Faculty of Chemistry Technion—Israel Institute of Technology Technion City Haifa 3200009 Israel
| |
Collapse
|
12
|
Cohen Y, Cohen A, Marek I. Creating Stereocenters within Acyclic Systems by C–C Bond Cleavage of Cyclopropanes. Chem Rev 2020; 121:140-161. [DOI: 10.1021/acs.chemrev.0c00167] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yair Cohen
- Schulich Faculty of Chemistry, Technion − Israel Institute of Technology, Technion City, Haifa 3200009, Israel
| | - Anthony Cohen
- 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
| |
Collapse
|
13
|
Fernandes RA, Kumar P, Choudhary P. Advances in catalytic and protecting-group-free total synthesis of natural products: a recent update. Chem Commun (Camb) 2020; 56:8569-8590. [PMID: 32537619 DOI: 10.1039/d0cc02659j] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Catalytic processes in protecting-group-free syntheses of natural products are fast emerging towards achieving the goal of efficiency and economy in total synthesis. Present day sustainable development in synthesis of natural products does not permit the luxury of using stoichiometric reagents and protecting groups. Catalysis and step-economy can contribute significantly toward economy and efficiency of synthesis. This feature article details the ingenious efforts by many researchers in the last couple of years toward concise total syntheses, based on catalytic steps and protecting-group-free-strategies. These would again serve as guidelines in future development of reagents and catalysts aimed at achieving higher efficiency and chemoselectivity to the point that catalysis and protecting-group-free synthesis will be an accepted common practice.
Collapse
Affiliation(s)
- Rodney A Fernandes
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, Maharashtra, India.
| | | | | |
Collapse
|
14
|
Cohen A, Chagneau J, Marek I. Stereoselective Preparation of Distant Stereocenters (1,5) within Acyclic Molecules. ACS Catal 2020. [DOI: 10.1021/acscatal.0c01762] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Anthony Cohen
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa, 32000, Israel
| | - Jean Chagneau
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa, 32000, Israel
| | - Ilan Marek
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa, 32000, Israel
| |
Collapse
|
15
|
Lanke V, Marek I. Nucleophilic Substitution at Quaternary Carbon Stereocenters. J Am Chem Soc 2020; 142:5543-5548. [DOI: 10.1021/jacs.0c01133] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Veeranjaneyulu Lanke
- Schulich Faculty of Chemistry, Technion − Israel Institute of Technology, Technion City 3200009, Haifa, Israel
| | - Ilan Marek
- Schulich Faculty of Chemistry, Technion − Israel Institute of Technology, Technion City 3200009, Haifa, Israel
| |
Collapse
|
16
|
|
17
|
|