CARBON-OXYGEN BOND INSERTION IN THE REACTION OF DIALKOXYCARBENES WITHANHYDRIDES

Dimethoxycarbene (1a) and methoxy(2,2,2-trifluoroethoxy)carbene (1b) w ere generated in benzene solution by thermolysis of the corresponding 2,2-dialkoxyoxadiazolines 7. The carbenes were trapped by intermolecul ar reaction with a variety of cyclic anhydrides 8. The products 9 are formally the result of carbene insertion into the bond between the car bonyl carbon and the ring oxygen atoms. The results of a competition b etween dimethylmaleic and dichloromaleic anhydrides for dimethoxycarbe ne suggests that this reaction proceeds by nucleophilic attack of dial koxycarbene onto the carbonyl carbon atom of the anhydride.