A highly enantioselective asymmetric Darzens reaction catalysed by proline based efficient organocatalysts for the synthesis of di- and tri-substituted epoxides
A new class of easily available and readily tunable proline based chiral organocatalysts was found to efficiently catalyse an unprecedented highly enantioselective asymmetric Darzens reaction of α-chloro ketones and substituted α-chloro ketones with various aldehydes, which directly produces optically active di- and tri-substituted chiral epoxides with higher product yields (up to 97 %) and excellent
Waste minimization is a very important aspect of an environmentally benign protocol. A one-pot consec-process has been developed for chalcone epoxide synthesis that allows compounds to be prepared having to isolate and purify the intermediates. The strategy utilizes consecutive Claisen Schmidt and epoxidation reactions to prepare chalcone epoxides from substituted benzaldehydes acetophenones in good yields. (C) 2014 Elsevier Ltd. All rights reserved.
Visible-Light-Promoted Photoredox Syntheses of α,β-Epoxy Ketones from Styrenes and Benzaldehydes under Alkaline Conditions
作者:Jing Li、David Zhigang Wang
DOI:10.1021/acs.orglett.5b02629
日期:2015.11.6
A range of styrenes and benzaldehydes were smoothly combined to form alpha,beta-epoxy ketones under the synergistic actions of photocatalyst Ru(bpy)(3)Cl-2, tert-butyl hydroperoxide (t-BuOOH), cesium carbonate (Cs2CO3), and visible light irradiation. The process likely proceeds through visible-light-enabled photocatalytic generations of acyl radicals as key intermediates.
Regioselective Opening of Chalcone Epoxides with Nitrogen Heterocycles Using Indium(III) Chloride as an Efficient Catalyst
作者:Naveen Kumar Konduru、Naseem Ahmed
DOI:10.1080/00397911.2012.667291
日期:2013.8.3
Indium(III) chloride catalyzes regioselective ring opening of chalcone epoxides with nitrogen heterocycles such as indole, 2-methyl indole, and pyrrole under mild conditions at room temperature to afford 1,3-diaryl-2-hydroxy-3-(1H-3-indolyl/2-pyrrolyl)propan-1-ones in good yields (6088%) within 2050min. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications (R) to view the free supplemental file.