Enantioselective Construction of All-Carbon Quaternary Centers by Branch-Selective Pd-Catalyzed Allyl–Allyl Cross-Coupling
作者:Ping Zhang、Hai Le、Robert E. Kyne、James P. Morken
DOI:10.1021/ja2039248
日期:2011.6.29
The Pd-catalyzed cross-coupling of racemic tertiary allylic carbonates and allylboronates is described. This reaction generates all-carbonquaternarycenters in a highly regioselective and enantioselective fashion. The outcome of these reactions is consistent with a process that proceeds by way of 3,3'-reductive elimination of bis(η(1)-allyl)palladium intermediates. Strategies for distinguishing the
Regioselective Hydroacylation of 1,3-Dienes by Cobalt Catalysis
作者:Qing-An Chen、Daniel K. Kim、Vy M. Dong
DOI:10.1021/ja500268w
日期:2014.3.12
We describe a cobalt-catalyzed hydroacylation of 1,3-dienes with non-chelating aldehydes. Aromatic aldehydes provide 1,4-addition products as the major isomer, while aliphatic aldehydes favor 1,2-hydroacylation products. The kinetic profile supports an oxidative cyclization mechanism involving a cobaltacycle intermediate that undergoes transformation with high regio- and stereoselectivity.