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Asymmetric Conjugate Addition of Unmodified Cyclic Ketones to Nitroolefins Using Aminophosphonate as the Organocatalyst
Author(s) -
CHEN Gang,
WANG Zheng,
DING Kuiling
Publication year - 2009
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.200990011
Subject(s) - chemistry , enantiopure drug , conjugate , catalysis , adduct , organocatalysis , proline , enantioselective synthesis , michael reaction , addition reaction , organic chemistry , combinatorial chemistry , amino acid , biochemistry , mathematical analysis , mathematics
α ‐Aminophosphonates are an important class of compounds with diverse and useful biological activities. Despite that their structues are similar to that of proline, however, chiral cyclic α ‐aminophosphonates have found little applications in catalytic asymmetric synthesis. In this paper, an enantiopure α ‐aminophosphonate has been synthesized and was found to be effective as a chiral organocatalyst for the asymmetric conjugate addition of cycloketones to β ‐nitrostyrenes. With a catalyst loading of 20 mol% and in the presence of 10 mol% of CF 3 COOH as a cocatalyst, the Michael adducts could be obtained with varying degrees of diastereo‐ and enantioselectivities (up to 97:3 and 90% ee respectively) under solvent‐free conditions.