Base-catalyzed transfer of the diazo moiety to a methylene group adjacent to one or more electron-withdrawing groups is a well established and powerful synthetic tooL2 The most commonly used reagent for diazo transfer has been p-toluenesulfonyl (tosyl) azide, 3 although isolated incidences of diazo transfer to@-dicarbonyl systems by other reagents have been rep~ rted.~~~ Difficulties have been reported in the chromatographic ...
