SOME TRANSFORMATIONS OF ADDUCTS OF DICHLOROCARBENE AND 7-SUBSTITUTED BENZONORBORNADIENES

The addition of dichlorocarbene to norbornene (l),1 norbornadiene (2),1and benzonorbornadiene (3)2provides the most direct route to compounds containing the bicy-clo[3.2.1]octyl ring system. The reaction involves addition of the carbene to the exo face of the bicyclic alkene to give initially a gem-dichlorocyclopropane, which under the rection conditions usually undergoes ring opening to afford a rearranged, ring-expanded dihalide, e.g. 6. In the reaction involving norbornene (1), the initial adduct 4 has been isolated, but in the case of norbornadiene (2) and benzo- (3), the ring-expanded products have been obtained directly1,2. © 1990, American Chemical Society. All rights reserved.