methyl(methylimino)diphenylsulfonium tetraphenylborate (3) with NaH and subsequent acylation produced a new type of iminosulfonium ylides bearing an α-carbonyl group 5. The molecular structure of iminosulfonium phenacylide 5a was determined by X-ray crystallographic analysis. The ylide 5 reacted further with methyl triflate affording the corresponding novel alkylidenesulfonium salts 6.