Asymmetric Transfer Hydrogenation of Aromatic Ketones

摘要

PURPOSE: An asymmetric hydrogen transfer reducing method of aromatic ketone compounds is provided, therefore the cost for reduction can be decreased because L-proline as a ligand is cheap, and the optical purity and reduction yield of aromatic ketone compounds can be maximized. CONSTITUTION: The asymmetric hydrogen transfer reducing method of aromatic ketone compounds is carried out in the presence of a ligand of formula(2), ruthenium(II) catalysts, and a reducing agent of formic acid or alkoxy metal salt. In the formula, R is phenyl, 1 or 2 fluoro or methoxy group substituted phenyl, or naphthalene; the ruthenium(II) catalyst is selected from (RuCl2Ph)2, (RuCl2(p-cvm))2 and (RuCl2(Me6C6))2; the mole ratio of ligand to ruthenium(II) used is 1:1 to 4:1; the volume ratio of formic acid to triethylamine is 1:2 to 2:1; the alkoxy metal salt is methoxy alkali metal salt, ethoxy alkali metal salt or propoxy alkali metal sa the reducing solvent is selected from dimethylformaldehyde, dichloroethane and acetonitrile; and temperature of the reduction reaction is 20 to 50 deg. C.