Intramolecular diels‐alder reactions. IX. Syntheses of N‐benzylcyclolignan lactams

Abstract
Four bis‐unsaturated N‐benzyl amides of the type where (C2) and (C2)' are variously trans‐CHCH and CC groups, were synthesized and refluxed in acetic anhydride. Three of them cyclized to form N‐benzylcyclolignan lactams by intramolecular Diels‐Alder processes. In one case [(C2)  CC, (C2)'  trans‐CHCH] the (C2) unit functioned as the dienophilic moiety.