Palladium-catalysed borylsilylation and borylstannylative dimerization of 1,2-dienes
作者:Shun-ya Onozawa、Yasuo Hatanaka、Masato Tanaka
DOI:10.1039/a905127i
日期:——
A borylsilane regioselectively adds to 1,2-dienes in the presence of palladium complexes to afford high yields of alkenylboranes having allylsilane moieties, whereas a borylstannane gives a 1 : 2 telomer with 3-methylbuta-1,2-diene due to borylstannylative dimerization.
A highly regio‐ and stereoselective copper‐catalyzed borylcupration of 1,2‐allenylsilanes affords an unexpected regioreversed allylic boronate bearing an extra C−Si bond at the 3‐position, with a thermodynamically disfavored Z geometry. Such stereodefined allylic boronates containing an extra alkenyl silane moiety are very useful organodimetallic reagents for organic synthesis.
NHC–Cu-Catalyzed Protoboration of Monosubstituted Allenes. Ligand-Controlled Site Selectivity, Application to Synthesis and Mechanism
作者:Fanke Meng、Byunghyuck Jung、Fredrik Haeffner、Amir H. Hoveyda
DOI:10.1021/ol4004178
日期:2013.3.15
Two types of NHC-Cu complexes catalyze protoborations of terminal allenes to afford valuable 1,1- or trisubstituted vinylboron species with high site selectivity and stereoselectivity. The scope of the method, application to natural product synthesis, and mechanistic basis for the observed selectivity trends are presented.
<i>β</i>-Borylallylsilanes as a New Tool for Convenient Synthesis of Alkenylboranes