Pyrrolidine–oxyimide catalyzed asymmetric Michael addition of α,α-disubstituted aldehydes to nitroolefins
作者:Togapur Pavan Kumar
DOI:10.1016/j.tetasy.2015.07.009
日期:2015.9
Organocatalyticenantioselective Michael addition of α,α-disubstituted aldehydes onto nitroolefins using pyrrolidine–oxyimide catalyst was reported. The reaction works effectively under neat conditions with 15 mol % of catalyst and 10 mol % of p-nitrobenzoic acid as an additive at 0 °C; this results in the formation of Michael adducts possessing an all-carbon quaternarycenter with good yields and
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
Enantioselective Michael addition of aldehydes to nitroolefins catalyzed by pyrrolidine-HOBt
作者:Togapur Pavan Kumar、Mohammad Abdul Sattar、Sthanikam Siva Prasad、Kothapalli Haribabu、Cirandur Suresh Reddy
DOI:10.1016/j.tetasy.2017.02.005
日期:2017.3
The oxytriazole catalyst "pyrrolidine-HOBt" developed for asymmetric Michael addition of cyclohexanone to nitroolefins is now evaluated for the asymmetric Michael addition of aldehydes to nitroolefins under similar reaction conditions. The results of this study indicate that, the oxytriazole catalyst "pyrrolidine-HOBt" is equally effective in promoting the Michael addition of aldehydes to nitroolefins on employing benzoic acid as an additive. The desired products, gamma-nitrocarbonyl compounds were obtained in good yields and high enantioselectivities. (C) 2017 Elsevier Ltd. All rights reserved.