Stereoselective synthesis of optically active pyridyl alcohols via asymmetric transfer hydrogenation of pyridyl ketones

A chiral Ru(II) complex, RuCl[(S,S)-N-(p-toluenesulfonyl)-1,2-diphenyl-ethylenediamine](p-cymene), serves as an efficient catalyst for asymmetric transfer hydrogenation of 2-acetylpyridine with a substrate to catalyst molar ratio of 200–1000 with HCOOH as a hydrogen source to give (S)-1-(2-pyridyl)ethanol in an almost quantitative yield and with 95% ee.