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 keteneacetals 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
Radical-chain functionalisation at C–H centres using an O-oxiranylcarbinyl O-silyl ketene acetal
作者:Yudong Cai、Hai-Shan Dang、Brian P. Roberts
DOI:10.1016/j.tetlet.2004.03.165
日期:2004.5
A readily prepared O-oxiranylcarbinyl O-silyl ketene acetal has been used to bring about functionalisation at various types of saturated C-H group, through the intermediacy of an oxiranylcarbinyl radical that undergoes rapid ring opening to give a highly reactive allyloxyl radical. (C) 2004 Elsevier Ltd. All rights reserved.
Carboncarbon bond formation by radical addition–fragmentation reactions of O-tert-alkyl enols and O-cyclopropylcarbinyl enols
作者:Yudong Cai、Brian P Roberts
DOI:10.1016/s0040-4039(03)01092-x
日期:2003.6
Terminal alkenes of the type H(2)C=C(OR(1))X, in which R(1) is a tertiary alkyl or a 1-cyclopropylethyl group and X=Ph, OSiMe(2)Bu', OEt or H, undergo radical-chain reactions with organic halides R(2)Hal to give carbonyl compounds R(2)CH(2)C(=O)X. (C) 2003 Elsevier Science Ltd. All rights reserved.