Reaction of diethyl dibromomalonate (1) with sodium methoxide in cyclohexene yields dibromonorcarane (2) as the major product. This product forms via the capture of dibromocarbene (4) by cyclohexene. Dibromocarbene, in turn, is generated from ethyl tribromoacetate (6) which evidence suggests arises via a bromophilic attack between the carboethoxydibromomethyl carbanion (7) and diethyldibromomalonate (1).
