Asymmetric Transfer Hydrogenation of Arylidene-Substituted Chromanones and Tetralones Catalyzed by Noyori–Ikariya Ru(II) Complexes: One-Pot Reduction of C═C and C═O bonds

Abstract

3-Arylidenechroman-4-ones and 2-arylidene-1-tetralones are hydrogenated to <i>cis</i>-benzylic alcohols in dr's and er's up to 99:1 via a C═C and C═O one-pot reduction in the presence of 2-5 mol % Noyori-Ikariya-type Ru^II chiral complexes and HCO₂Na as a hydrogen source under asymmetric transfer hydrogenation-dynamic kinetic resolution (ATH-DKR) conditions. The oxidation of theses substrates resulted in the enantioselective synthesis of the natural homoisoflavanone dihydrobonducellin and its carba-analogues.