Abstract: Sodium alkoxides react with 1-bromo-1-alkynes in refluxing benzene, toluene. or xylene solutions by proton abstraction at C-3 generating an intermediate zwitterion-carbene, which in the presence of equimolar quantities of alcohol (or alkoxide) gives four products. Mechanisms involving nucleophilic attack by alcohol (alkoxide) on the ambident vinylidene carbene, prototropic rearrangement, and carbene insertion into the carbon-hydrogen ...