Diazomethane add to the enyne sulfones 1, 3, 4, 6-11 regio- and stereo
-selectively to give the -alkynyl-5-phenylsulfonyl-4,5-dihydro-3H-pyra
zoles 12-15 and 17-19, which are converted by MeLi into the 4-alkynyl-
1N-pyrazoles 24, 25, 16, 26, 28, 30 in good yields, 4,5-Bis(alkynyl)-1
H-pyrazoles 34, 37 are also obtained by the same procedure.