Catalytic Asymmetric Cycloaddition of Ketenes and Nitroso Compounds:Enantioselective Synthesis of alpha-Hydroxycarboxylic Acid Derivatives

摘要

Enantioenriched alpha-hydroxycarboxylic acid derivatives are not only present as sublimits in a range of bioactive compounds,but they also serve as useful intermediates in organic chemistry.Consequently,the development of efficient and versatile methods for their synthesis is an important objective.In the case of a-hydroxycarboxylic acid derivatives wherein the alcohol group is tertiary,several catalytic asymmetric routes have been described,such as the cyano-silylation of ketones,the addition of organometallic reagents to alpha-ketoesters,and the phase-transfer alkylation of oxazolidin-2,4-diones.Nevertheless,the development of methods with broader scope is desirable.'61