PREPARATION AND REACTIVITY OF ARYLSULFONYL SUBSTITUTED CYCLOPROPENES

Article abstract of DOI:10.1016/S0040-4020(01)86547-9

A study of the cycloaddition behaviuor of several arylsulfonyl substituted alkynes with 2-diazopropane has been carried out.These activated acetylenes react to give 3H-pyrazoles which extrude nitrogen on photolysis to produce cyclopropenes in high yield.Soft nucleophiles such as thiophenoxide readily add to the activated pi-bond to give thiophenyl substituted cyclopropanes.Reaction of 1-phenylsulfonyl-2,3,3-trimethylcyclopropene with n-butyllithium followed by alkylation with various electrophiles produces arylsulfonyl substituted methylene cyclopropanes.These compounds undergo thermal rearrangement to the thermodynamically more stable isopropylidene cyclopropane.