Vicinal alkylation–carboxymethylation of electron-poor alkenes by radical-chain reactions with O -alkyl O -silyl ketene acetals and their [3+2] annulation by reaction with O -cyclopropylcarbinyl O -silyl ketene acetals
作者:Yudong Cai、Brian P. Roberts
DOI:10.1016/j.tetlet.2003.12.045
日期:2004.2
O-Silyl ketene acetals of the type H2CC(OR)OSiMe2But, in which R is a tertiary or secondary alkyl group, react with electron-poor alkenes to bring about vicinal alkylation–carboxymethylation of the latter. When R is a cyclopropyldimethylcarbinyl group such reactions take a more complex course involving ring opening of the cyclopropylcarbinyl radical and lead ultimately to [3+2] annulation of the alkene
ø -甲硅烷基乙烯酮的H型的缩醛2 CC(OR)OSiMe 2卜吨,其中R是叔烷基或仲烷基,与缺电子烯烃反应以实现后者的连位烷基化,羧甲基化。当R是环丙基二甲基羰基时,这种反应采取更复杂的过程,包括环丙基羰基自由基的开环并最终导致烯烃的[3 + 2]环化。