Condensed cyclic and bridged-ring systems. Part V. Application of the interamolecular oxo-carbenoid insertion reaction to the preparation of two new bridged-ring ketones

Two new bridged-ring ketones, 5,6,7,8,10,11-hexahydro-8,12-dimethyl-5,8,11-ethan[1]yl[2]ylidenebenzocyclononen-9-one (5) and 1,3,3a,4,9,9a-hexahydro-1,3a-dimethyl-1,4-ethanocyclopenta[b]naphthalen-2-one (6), have been synthesised by intramolecular oxo-carbenoid C-H insertion reactions in the copper-catalysed decomposition of the 8-diazoacetyl-5,6,7,8,9,10-hexahydro-8,11-dimethyl-5,9-methanobenzocyclo-octenes (3) and (4), epimeric at position 8