Transannular reactions in the dibenzo[a,d]cycloheptene series. IV. 10,5 Ketone–amide interactions

Abstract

10-Ketodibenzocycloheptene-5-carboxamides undergo transannular interactions to form carbinolamides. This approach has been used to prepare a number of 11-substituted and -unsubstituted-10,11-dihydro-10,5-(iminomethano)-5H-dibenzo[a,d]cycloheptenes. The ketolactone 3 was a convenient starting material for the substituted compounds. It reacted readily with primary amines to give the carbinolamides 7 or 8, and underwent equally rapid transformations with secondary amines or alkali to furnish products derived from aerial oxidation, decarboxylation, ring contraction, and/or dimerization. The epoxynitrile 20 was converted by a 5-step sequence to the ketocarboxamide 27 which cyclized at once to the 11-unsubstituted carbinolamide 28. A modification of this sequence gave the carbinolamine 31.