The efficient enantioselective synthesis of dihydropyrans via organocatalytic Michael addition reactions
作者:Zhiqiang Niu、Xinwei He、Yongjia Shang
DOI:10.1016/j.tetasy.2014.04.014
日期:2014.5
An asymmetric Michaeladdition of α-cyanoketones to α,β-unsaturated aldehydes to form chiral dihydropyrans catalyzed by l-diphenylprolinol trimethylsilyl ether is presented. A series of 3,4-dihydropyrans were obtained in excellent yields (up to 91%) and enantioselectivities (up to 98% ee). A plausible mechanism for this process is proposed.
A stereoselective sequential organocascade and multicomponent approach for the preparation of tetrahydropyridines and chimeric derivatives
作者:Radell Echemendía、Gustavo P. da Silva、Meire Y. Kawamura、Alexander F. de la Torre、Arlene G. Corrêa、Marco A. B. Ferreira、Daniel G. Rivera、Márcio W. Paixão
DOI:10.1039/c8cc06871b
日期:——
A stereoselective multicomponent approach leading to a novel class of pentasubstituted tetrahydropyridines is described. Variation of the components enabled the incorporation of peptide, sugar and steroid moieties to access chimeric derivatives. DFT calculations provide insights about the unprecedented high diastereoselectivity of the MCR.