Process for producing an optically active 2-substituted propanal derivative

The present invention relates to a method for producing an optically active 2-substituted propanal derivative, more particularly, 2 carbon atoms of the substituted acrolein derivatives - carbon double bond, the carbon - ability to reduce carbon double bond stereoselectively by stereoselectively reduced using an enzyme source having, a method for producing an optically active 2-substituted propanal derivative. According to the present invention, useful optically active 2-substituted propanal derivative as an intermediate for pharmaceutical products and sweeteners, especially the optically active 2-alkyl-propanal derivative is prepared by a simple method from readily raw material available at low cost be able to.