Deciphering the Origin of Enantioselectivity on the Cis-Cyclopropanation of Styrene with Enantiopure Di-chloro,Di-gold(I)-SEGPHOS Carbenoids Generated from Propargylic Esters

Autor:	Adán B. González-Pérez, Pedro Villar, Angel R. de Lera
Rok vydání:	2019
Předmět:	chemistry.chemical_compound SEGPHOS Enantiopure drug chemistry Cyclopropanation Organic Chemistry Stereoselectivity Carbene Medicinal chemistry Cycloaddition Styrene Cyclopropane
Zdroj:	The Journal of Organic Chemistry. 84:7664-7673
ISSN:	1520-6904 0022-3263
DOI:	10.1021/acs.joc.9b00250
Popis:	The stereoselective synthesis of cis-disubstituted cyclopropanes by the Au(I)/PPh3-catalyzed cycloaddition of propargylic esters and styrene has been studied using density functional theory calculations. The computed mechanistic scheme involves the rate-limiting 1,2-rearrangement of the propargylic ester with the π-coordinated gold complex, followed by the (2 + 1)-cheletropic reaction of styrene with the alkenyl–Au(I) carbene intermediate to afford the cis-disubstituted cyclopropane derivative in a high cis/trans diastereomeric ratio. With a (R)-di-chloro,di-gold-DTBM-SEGPHOS complex as the catalyst, computations are consistent with a rate-determining (2 + 1)-cheletropic reaction, in which facial discrimination is proposed to result from a combination of subtle steric and electronic effects in the SiRe facial approach transition structure, which favor the formation of the cis-cyclopropane diastereomer of 1R,2S absolute configuration, as experimentally observed.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0a2528a7773ee46a2b53764a873543e6 https://doi.org/10.1021/acs.joc.9b00250 Zobrazit plný text záznamu