A chemoselective 1,2-reduction of cycloalkyl vinyl ketones via asymmetric transfer hydrogenation is described. The reduction proceeded smoothly with a chiral diamine ruthenium complex as a catalyst and a HCOOH–NEt3 azeotrope as both a hydrogen source and solvent under mild conditions. A wide range of 1-cycloalkyl chiral allylicalcohols were obtained in good yields and up to 87% ee. It was found that