Ag(I)-Catalyzed Cyclizative Hydration of Alkynes and Propargylic Alcohols. A Mild Approach to 2-Acylfuran Derivatives

We developed a mild strategy for the synthesis of 2-acylfuran derivatives via cyclizative hydration of propargylic alcohols and alkynes, under Ag(I) catalysis. This is the first report employing the propargylic alcohols and their derivatives as alkyne partners in the cyclizative hydration process. This process found very broad scope for propargylic alcohols, alkynes and tethers. The highly chemo-selective cyclizative hydration of 6-acetoxy-hex-2-en-4-ynal substrates suggests that, the acetoxy directed hydration of alkyne is not operable under Ag-catalysis conditions and hence propargylic acetates can also be conveniently employed for the synthesis of 2-(acetoxyacyl)furans.