NOVEL AND CONVENIENT ROUTES TO FUNCTIONALIZED ALKYNYL KETONES FROM 1-(BENZOTRIAZOL-1-YL)PROPARGYL ETHYL ETHERS

1-(Benzotriazol-1-yl)propargyl ethyl ethers, readily accessible from propargyl aldehyde diethyl acetals and benzotriazole, undergo smooth Lithiation at the methine carbon and subsequent reactions with alkyl halides, aldehydes, ketones, imines, esters, trialkylsilyl chlorides, dialkyl carbonates, and isocyanates to yield the corresponding substituted ethers. Hydrolysis of these intermediates under acidic conditions affords a wide variety of alkynyl ketones bearing hydroxy, amino, acyl, trimethylsilyl, alkoxycarbonyl, and (alkylamino)carbonyl substituents at the alpha-position in good to excellent overall yields.