Asymmetric Synthesis of 3,4-Dihydrocoumarins Bearing an α,α-Disubstituted Amino Acid Moiety
作者:Joanna Hejmanowska、Anna Albrecht、Jakub Pięta、Łukasz Albrecht
DOI:10.1002/adsc.201500598
日期:2015.12.14
An organocatalytic approach for the stereoselective synthesis of 3,4-dihydrocoumarins with an α,α-disubstituted amino acid moiety incorporated is presented. The developed methodology is based on the cascade reaction between α-substituted azlactones and 2-hydroxychalcones. It is initiated by a chiral Brønsted base-catalyzed enantio- and diastereoselective Michael reaction followed by the azlactone ring
A one-pot method for the selective synthesis of twoisomers 4H-chromene and 2,8-dioxabicyclo[3.3.1]nonane derivatives was developed without a catalyst and using EtOH/H2O (4:1, v/v) as the solvent. The reaction was conducted under mild conditions, with forming multiple chemical bonds in one pot and high atom economy, and only a stoichiometric amount of H2O is produced as the byproduct. Its selectivity
开发了一种选择性合成两种异构体 4 H -色烯和 2,8-二氧杂双环 [3.3.1] 壬烷衍生物的一锅法,无需催化剂,使用 EtOH/H 2 O (4:1, v/v)作为溶剂。该反应在温和的条件下进行,一锅形成多个化学键,原子经济性高,副产物仅产生化学计量的H 2 O。其选择性受热力学和动力学控制,并讨论了两种结构发生转变的原因。
Reactions of 2-hydroxyaryl-α,β-unsaturated ketones with dimethylsulfonium carbonylmethylides: a new and facile diastereoselective synthesis of 2,3-disubstituted dihydrobenzofurans
作者:Sarika Malik、Upender K. Nadir、Pramod S. Pandey
DOI:10.1016/j.tet.2009.02.041
日期:2009.5
A simple, efficient, and general method has been developed for the diastereoselective synthesis of 2,3-disubstituted dihydrobenzofurans through reactions of 2-hydroxyaryl-α,β-unsaturated ketones with dimethylsulfonium carbonylmethylides.