Aminothiocarbamate-Catalyzed Asymmetric Bromolactonization of 1,2-Disubstituted Olefinic Acids
作者:Chong Kiat Tan、Ling Zhou、Ying-Yeung Yeung
DOI:10.1021/ol200840e
日期:2011.5.20
An efficient and enantioselectivebromolactonization of 1,2-disubstituted olefinicacids using an amino-thiocarbamate catalyst has been developed, resulting in the formation of δ-lactones containing two chiral centers with up to 99% yield, 95% ee.
Studies on Thiourea Catalysed Bromocycloetherification and Bromolactonisations
作者:Venkatachalam Pitchumani、David W. Lupton
DOI:10.1071/ch20184
日期:——
Lewis base catalysed halofunctionalisation reactions of alkenes are well established and allow access to, among others, various oxygen containing heterocycles. By exploiting the known conversion of N-heterocyclic carbenes into the corresponding thioureas it has been possible to prepare and study a range of chiral and non-chiral Lewis base catalysts for such reactions. Although all thiourea catalysts
strained olefins in trans‐cyclooctenes serve as efficient catalysts for halolactonizations, including bromolactonizations and iodolactonizations. The trans‐cyclooctene framework is essential for excellent catalytic performance, and the substituents also play important roles in determining efficiency. These results are the first demonstration of catalysis by a trans‐cyclooctene.