Asymmetric phase-transfer catalytic sulfanylation of some 2-methylsulfinyl cyclanones. Modeling of the stereochemical course of the aldol reaction of (SS,2S)-2-methylsulfinyl-2-methylsulfanylcyclohexanone

Autor:	Paulo R. Olivato, José E. P. Cardoso FilhoJ.E.P. Cardoso Filho, Liliana Marzorati, Blanka Wladislaw, Alessandro Rodrigues, Claudio Di Vitta, Mauro Alves Bueno
Rok vydání:	2010
Předmět:	Chemistry Stereochemistry ESTEREOQUÍMICA Organic Chemistry Ethyl acetate chemistry.chemical_element Biochemistry Catalysis Hydrolysis chemistry.chemical_compound Aldol reaction Nucleophile Drug Discovery Lithium Density functional theory Conformational isomerism
Zdroj:	Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP
ISSN:	0040-4039
DOI:	10.1016/j.tetlet.2010.08.010
Popis:	Increased diastereoisomeric excesses are obtained for the sulfanylation reactions of some 2-methylsulfinyl cyclanones under phase-transfer catalysis using the chiral catalyst QUIBEC instead of TEBA. The optically pure (SS,2S)-2-methylsulfinyl-2-methylsulfanylcyclohexanone thus prepared reacts with ethyl acetate lithium enolate affording, after hydrolysis, (R)-2-[(ethoxycarbonyl)methyl]-2-hydroxycyclohexanone in 60% ee. Density functional theory calculations (at the B3LYP/6-311++G(d,p) level) can successfully explain the origin of this result as the kinetically favored axial attack of the nucleophile to the carbonyl group of the most stable conformer of the cyclanone, in which the CH3SO and CH3S groups are at the equatorial and axial positions, respectively.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5ca39103cdc935535a256bf04ed1cc89 https://doi.org/10.1016/j.tetlet.2010.08.010 Zobrazit plný text záznamu Full Text from ScienceDirect