One-Pot Synthesis of alpha,beta-Unsaturated Esters, Ketones, and Nitriles from Alcohols and Phosphonium Salts

A general method for the synthesis of ,-unsaturated esters, ketones, and nitriles is successfully achieved by a one-pot copper-catalyzed oxidation with O-2 in air as oxidant. The solvent mixture of acetonitrile and formamide (1:1) is optimized to ensure the oxidation of alcohols, deprotonation of phosphonium salt, and Wittig reaction occur efficiently in one pot. A broad range of substrates has been explored for this process, including three electron-withdrawing group (CO2 Et, COPh, CN) functionalized phosphonium salts. They reacted not only with benzylic and heteroaromatic alcohols, but also with aliphatic alcohols, forming the corresponding ,-unsaturated esters, ketones, and nitriles in moderate to excellent yields.