Tetrahedron

Dipolar cycloaddition reaction of diazoalkanes with trimethylsilyl substituted alkynes. Steric control of regiochemistry by the trimethylsilyl group

A Padwa, MW Wannamaker

Index: Padwa, Albert; Wannamaker, M. Woods Tetrahedron, 1990 , vol. 46, # 4 p. 1145 - 1162

Full Text: HTML

Citation Number: 42

Abstract

A study of the cycloaddition behavior of several trimethylsilyl substituted alkynes with 2- diazopropane and diazomethane has been carried out. Aryl or alkyl ethynyl sulfones react to give 5-sulfonyl substituted 3H-pyrazoles which extrude nitrogen on photolysis to produce cyclopropenes in high yield. The regiochemical results are compatible with FMO considerations in that the favored adduct is the result of the union of the larger ...