Ethers from esters; from exceptional transformation to synthetic method

Most ether-bond forming reactions based on traditional methods or modifications thereof require strongly acidic or basic conditions and often harsh reaction conditions. Reduction of esters to ethers has been regarded as an impracticable method, generally affording alcohols as the principal products. Only recently, original, mostly catalytic methods for reduction of esters to ethers have been reported, which proceed under mild conditions and are compatible with many functional groups present in the substrate ester molecule. These reactions are considered as a valuable alternative to traditional methods, and specific protocols have been reported. An account of the progress in this synthetic methodology is given .