The reaction of stable sulfonium ylides of dimedone with triphenylphosphine

Abstract

1. Triphenylphosphine demethylates 2-(methylphenylsulfuranylidene)-5,5-dimethylcyclohexane-1, 3-dione to form methyltriphenylphosphonium 2-(phenylthio)-5,5-dimethylcyclohexane-1,3-dione (IV). 2. Compound (IV) readily undergoes anion-exchange reactions with NaBPh4, MeI, moist SO2 (gas), dry HCl, and Me2SO4. 3. Dimethyl- and dibenzylsulfonium ylides of dimedone are desulfurized and deoxygenated by triphenylphosphine. © 1978 Plenum Publishing Corporation.