SYNTHESIS AND REACTIONS OF ALLENIC PHOSPHONIUM SALTS AND YLIDES

2-Bromo-3,3-diphenylallyltriphenylphosphonium bromide, upon treatment with 1 equiv of base, yields 3,3-diphenylallenyltriphenylphosphonium bromide, whereas excess base produces, in situ, a cumulative ylide (15). The allenylphosphonium salt is unreactive to methyl alcohol and t-butyl mercaptan, but adds aniline. This latter adduct can be dehydrohalogenated to an imino-stabilized phosphorus ylide (12) which reacts with aromatic aldehydes via the Wittig reaction. The cumulative ylide (15) undergoes Wittig reactions with aromatic aldehydes, aromatic isocyanates, and diphenylketene. © 1969, American Chemical Society. All rights reserved.