Decarboxylative radical addition to vinylsulphones and vinylphosphonium bromide: Some further novel transformations of geminal (pyridine-2-thiyl) phenylsulphones.
摘要:
Irradiation of O-acyl derivatives 1 of N-hydroxy- 2-thiopyridone with visible light in the presence of phenyl vinyl sulphone or vinyl triphenylphosphonium bromide leads to the corresponding adducts 8 and 9 which can undergo a wide variety of further transformations.
Conversion of Hydroxyl Groups in Alcohols to Other Functional Groups with<i>N</i>-Hydroxy-2-thiopyridone, and Its Application to Dialkylamines and Thiols
作者:Hideo Togo、Misa Fujii、Masataka Yokoyama
DOI:10.1246/bcsj.64.57
日期:1991.1
The radical decarboxylation reaction of N-alkoxyoxalyloxy-2-thiopyridone which was prepared by the reaction of alcohol, oxalyl chloride, and N-hydroxy-2-thiopyridone was studied both in the absence and presence of olefinic compounds. The same reactions with olefinic and acetylenic alcohols gave the corresponding lactone derivatives. On the other hand the unsymmetrical alkyl 2-pyridyl disulfides were obtained by the same reaction with aliphatic thiols.
B-Alkylcatecholboranes, easily prepared in situ by hydroboration of alkenes, are powerful radical precursors that can be used for carbon-carbon bond formation. Typical procedures for (a) conjugate addition to enones, (b) conjugate addition to activated alkenes such as vinyl sulfones, and (c) direct allylation are described. Experimentally, these three one-pot reactions are easy to perform. No slow
Radical addition to vinyl sulphones and vinyl phosphonium salts
作者:Derek H.R. Barton、Hideo Togo、Samir Z. Zard
DOI:10.1016/s0040-4039(01)84596-2
日期:——
Alkyl radicals, derived from decarboxylation of carboxylic acids, add readily to phenyl vinyl sulphone and vinylphosphonium bromide. The adducts may be further converted into a variety of useful synthetic intermediates.