Silicon Acceleration of a Tandem Alkene Isomerization/Electrocyclic Ring-opening of 2-Methyleneoxetanes to α,β-Unsaturated Methylketones
作者:Elisa Farber、Aleksandra Rudnitskaya、Santosh Keshipeddy、Kendricks S. Lao、José A. Gascón、Amy R. Howell
DOI:10.1021/jo4014645
日期:2013.11.15
The first rearrangement of 2-methyleneoxetanes to alpha,beta-unsaturated methylketones is reported. It is proposed that when these substrates are heated, the corresponding oxetenes are formed and subsequently undergo electrocyclic ring-opening to methyl vinylketones. In particular, alpha-silyl-alpha,beta-unsaturated methylketones were isolated in moderate to high yields and with high stereoselectivities. Based on the proposed mechanism, density functional theory explains the differential kinetics and stereoselectivities among substrates.