The Cinchona Primary Amine-Catalyzed Asymmetric Epoxidation and Hydroperoxidation of α,β-Unsaturated Carbonyl Compounds with Hydrogen Peroxide
作者:Olga Lifchits、Manuel Mahlau、Corinna M. Reisinger、Anna Lee、Christophe Farès、Iakov Polyak、Gopinadhanpillai Gopakumar、Walter Thiel、Benjamin List
DOI:10.1021/ja402058v
日期:2013.5.1
Using cinchona alkaloid-derived primary amines as catalysts and aqueous hydrogenperoxide as the oxidant, we have developed highly enantioselective Weitz-Scheffer-type epoxidation and hydroperoxidation reactions of α,β-unsaturated carbonylcompounds (up to 99.5:0.5 er). In this article, we present our full studies on this family of reactions, employing acyclic enones, 5-15-membered cyclic enones, and
Catalytic Asymmetric Epoxidation of α-Branched Enals
作者:Olga Lifchits、Corinna M. Reisinger、Benjamin List
DOI:10.1021/ja1037935
日期:2010.8.4
An asymmetric catalytic epoxidation of alpha-branched, alpha,beta-unsaturated aldehydes is presented. A highly synergistic combination of a primary cinchona-based amine and a chiral phosphoric acid was found to promote the reaction with excellent enantiocontrol for alpha-monosubstituted and alpha,beta-disubstituted enals.
Retention of configuration in the ritter-type substitution reaction of chiral β-arylthio alcohols through the anchimeric assistance of the arylthio group
作者:Akio Toshimitsu、Chitaru Hirosawa、Kohei Tamao
DOI:10.1016/s0040-4020(01)85367-9
日期:1994.1
In chiral alcohols bearing a phenylthio group at the β carbon atom. the hydroxy group is replaced by nitriles through the anchimericassistance of the phenylthio group to afford chiral amides with retention of configuration. This stereospecific Ritter-type reaction has been utilized in the conversion of chiral glycidol derivatives to chiral cyclic imino ethers such as oxazolines bearing an arylthio
Prompt Determination of Absolute Configuration for Epoxy Alcohols via Exciton Chirality Protocol
作者:Xiaoyong Li、Babak Borhan
DOI:10.1021/ja805058t
日期:2008.12.3
A microscale protocol for determination of absoluteconfigurations of 2,3-epoxy alcohols is described. 2,3-Disubstituted (cis and trans), 2,2-disubstituted, 2,2,3-trisubstituted, and 2,3,3-trisubstituted epoxy alcohols rendered prominent ECCD signals upon complexing with a Lewis acidic porphyrin tweezer and consequently provide straightforward assignment of chirality for epoxy alcohols. This method