Utilization of water as a reagent in regio- and stereoselective reactions

Utilization of water as a reagent as well as a solvent is an important topic in synthetic organic chemistry. This article describes recent progress of hydration and hydrolysis reactions catalyzed by transition metal complexes. Direct transformation of 1-alkynes into aldehydes by Ru(II)-catalyzed hydration has been developed. It has been long known as a textbook example that the hydration follows Markovnikov's rule to give ketones as a sole product. Mechanistic study of the transformation revealed that Ru(II)-yinylidene complexes presumably are not involved in the current hydration reaction, but Ru(IV)-hydride-vinylidene complexes are concerned. Ru(II)-catalyzed hydroamination and its application to heterocycle synthesis are also described. This paper also illustrates metal catalyzed hydrolysis of terminal epoxides, alkenyl esters and ethers. Hydrolytic kinetic resolution of some chiral terminal epoxides and vinyl ethers are also developed.