Allylation and benzylation of enolates derived from β-phenylselanyl silyl enol ethers
摘要:
alpha-Phenylselanyl gamma-unsaturated ketones were obtained through allylation of enolates generated by potassium t-butoxide cleavage of beta-phenylselanyl silyl enol ethers derived from alpha-phenylselanyl ketones. With enoxysilanes prepared from alpha-phenylselanyl aldehydes, O-allylation and O-benzylation of the corresponding enolates were also observed. (C) 1997 Elsevier Science Ltd.
alpha,alpha-Bis(phenylseleno)ketones have been synthesized by phenylselenenylation of enolates derived from alpha-phenylseleno ketones. Depending on the structure of the ketones, three experimental procedures were adopted.
Some novel routes to 1-hetero-substituted 1-vinylcyclopropanes
作者:Richard T. Lewis、William B. Motherwell
DOI:10.1016/s0040-4020(01)92235-5
日期:1992.2
carbonyl compounds and diethyl diazomethylphosphonate, can be efficiently trapped by alkenes to give alkylidene-cyclopropane adducts which undergo either [1,3] allylseleniderearrangement or oxidative selenoxide [2,3] sigmatropic rearrangement to produce 1-phenylseleno- or 1-hydroxy-1-vinylcyclopropanes respectively.
The BF3-mediated aldol reaction between benzaldehyde and beta-phenylselanyl enoxysilanes 1 derived from alpha-phenylselanylmethylketones has led to syn aldols 2 and alpha,alpha-bis(phenylselanyl) ketones 3 as by-products. Using tetrabutylammonium fluoride, the syn and anti aldols 2a were formed from 1a. Syn, syn-2-phenylselanyl 1,3-diols 5a and 5d were obtained by borane reduction of aldols 2a and 2d respectively. (C) 1998 Elsevier Science Ltd. All rights reserved.