New derivatives of the 1,2-benzodiazepine ring system

Abstract

The adducts 10, formed in high yield by condensations between the benzotriazole dianion 2 and enals 9, undergo smooth oxidation by manganese(IV) oxide to provide the expected conjugated enones. These then cyclise at varying rates, depending upon the substitution pattern around the enone function, by intramolecular Michael addition of the NHBoc group to provide examples 13 of a novel ring system based upon a 4,5,6,7-tetrahydro-1,2-benzodiazepine core. Allylic acetates 16 derived from the initial adducts 10 also undergo cyclisations via the derived π-allyl palladium complexes 15 to provide examples of the corresponding 4,5-dihydro-1,2-benzodiazepinenes 17, but in a less general manner.