Recently, the 4, 5-dihydro-3H-pyrazolium salts have been synthesized from the cycloaddition of the short-lived 1-(chloroalkyl)-1-aza-Zazoniaallenes 5I" l8 to various electron-rich alkenes in the presence of Lewis acids like SbCl,; similarly some 1, 2, 4-triazolo C-nucle~ sides'~ were prepared recently via the cycloaddition of 2, 3, 5-hi-O-benzoyl-~-D- ribofuranosyl cyanide to intermediates 5.