Stereselective cycloaddition of dibenzoxazepinium ylides to acetylenes and fullerene [C.sub.60]. Conformational behavior of 3-aryldibenzo[b,f]pyrrolo[1,2-d][1,4]oxazepine systems

Cycloaddition of dibenzoxazepinium ylides to acetylene carboxylates has led to cis-3-aryl-3,13b-dihydrodibenzo[b,f]pyrrolo[1,2-d][1,4]oxazepinecarboxylates, which has dehydrogenated to the corresponding pyrrole derivatives. Stereoselective cycloaddition of dibenzoxazepinium ylides to fullerene [C.sub.60] has given rise to fulleropyrrolidines with cis-configuration and restricted Ph group rotation is seen in the phenyl derivative.