The reactions of chloroform with sodium hydroxide to generate dichlorocarbene can be promoted enormously by use of both ultrasonic irradiation and trace of phase transfer catalyst. The reactions are usually completed in 10-15 min with good yields. E.g., adduct I was prepared in 92% yield from cyclohexene and CHCl3.

Key words: CHLORIDE, CHLOROFORM, PHASE TRANSFER CATALYSIS, CARBENE, ULTRASONIC, NSFC, METHONIUM COMPOUNDS