Studies in the cycloproparene series: Approaches to octahydrocyclopropa-[l]phenanthrenes

Abstract

Cycloaddition between 1,1'-bicyclohexenyl(3) and the perhalocyclopropenes (4) affords the la,1b,2,-3,4,5,6,7,8,9,9a,9b-dodecahydrocyclopropa[/]phenanthrenes (5). Whilst halides (5a,b) are resistant to dehydrohalogenation, the difluoro derivatives (5c,d) yield 1,2,3,4,5,6,7,8-octahydrophenanthrene-9-carbaldehyde (12) with base. Under debromination conditions compound (5d) is converted into 1,2,3,4,5,6,7,8,8a,10a-decahydrophenanthrene-9-carboxylic acid (14) probably by way of the ring strained cyclopropene (9).