Pyrrolidinyl-Camphor Derivatives as a New Class of Organocatalyst for Direct Asymmetric Michael Addition of Aldehydes and Ketones to β-Nitroalkenes
作者:Ying-Fang Ting、Chihliang Chang、Raju Jannapu Reddy、Dhananjay R. Magar、Kwunmin Chen
DOI:10.1002/chem.201000483
日期:——
Practical and convenient synthetic routes have been developed for the synthesis of a new class of pyrrolidinyl–camphor derivatives (7 a–h). These novel compounds were screened as catalysts for the direct Michael addition of symmetrical α,α‐disubstituted aldehydes to β‐nitroalkenes. When this asymmetric transformation was catalyzed by organocatalyst 7 f, the desired Michael adducts were obtained in
Pyrrolidine-Camphor Derivative as an Organocatalyst for Asymmetic Michael Additions of α,α-Disubstituted Aldehydes to β-Nitroalkenes: Construction of Quaternary Carbon-Bearing Aldehydes under Solvent-Free Conditions
Abstractmagnified imageA novel pyrrolidine‐camphor organocatalyst 3 was designed, synthesized and proven to be an efficient catalyst for the asymmetric Michael reaction. Treatment of α,α‐disubstituted aldehydes with β‐nitroalkenes in the presence of 20 mol% organocatalyst 3 and 20 mol% benzoic acid under solvent‐free conditions provided the desired Michael product possessing an all‐carbon quaternary center with high chemical yields (up to 99% yield) and high levels of enantioselectivities (up to 95% ee).
Highly efficient asymmetric organocatalytic Michael addition of α,α-disubstituted aldehydes to nitroolefins under solvent-free conditions
作者:Junpeng He、Qiankun Chen、Bukuo Ni
DOI:10.1016/j.tetlet.2014.03.107
日期:2014.5
with benzoic acid has been found to be an effective organocatalyst for Michaeladdition of α,α-disubstituted aldehydes with nitroolefins. The reaction provided the desired Michael products possessing all-carbon quaternary center with high yields (76–98%) and high levels of enantioselectivities (up to 97% ee) under solvent-free reaction conditions. The procedure presented is simple and makes this method