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Enantioselective Michael Addition of α‐Substituted Cyanoacetates to Vinyl Ketones Catalyzed by Bifunctional Organocatalysts
Author(s) -
Liu TianYu,
Li Rui,
Chai Qian,
Long Jun,
Li BangJing,
Wu Yong,
Ding LiSheng,
Chen YingChun
Publication year - 2006
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200600796
Subject(s) - bifunctional , stereocenter , enantioselective synthesis , thiourea , chemistry , michael reaction , organic chemistry , organocatalysis , catalysis , adduct , amine gas treating , aryl , alkyl , tertiary amine , polymer chemistry
A highly enantioselective Michael addition of α‐substituted cyanoacetates to vinyl ketones was accomplished in the presence of simple bifunctional thiourea/tertiary amine organocatalysts. A number of α‐aryl or alkyl cyanoacetates have been successfully applied to give multifunctional compounds with an all‐carbon‐substituted quaternary stereocenter in excellent enantioselectivities (82–97 % ee ) and yields (61–99 %). The optical pure adducts could be smoothly converted to variously structured β 2,2 ‐amino acid esters. Moreover, an interesting reaction model involving multiple hydrogen‐bonding interactions amongst the thiourea/tertiary amine catalyst and the reactants has been proposed based on the absolute configuration of the adduct and computational studies.