A visible-light promoted cascade of Glaser coupling/annulation has been developed for one-potsynthesis of polysubstituted pyrazoles from alkynes and hydrazines. The method features mild reaction conditions, readily availible starting materials and green oxidant (O2). It works for a wide range of substituted phenyl acetylene and hyrazines with good functional group tolerance and efficiency. Mechanistic
Synthesis of 3,5-Disubstituted Pyrazoles via Cope-Type Hydroamination of 1,3-Dialkynes
作者:Liangguang Wang、Xiaoqiang Yu、Xiujuan Feng、Ming Bao
DOI:10.1021/jo302732v
日期:2013.2.15
An efficient method for the synthesis of 3,5-disubstituted pyrazoles is described. The reactions of 1,3-dialkynes with hydrazine proceeded smoothly in dimethyl sulfoxide under mild reaction conditions to produce 3,5-disubstituted pyrazoles in satisfactory to excellent yields. A one-pot procedure of the transformation has been developed.