Atom- and Step-Economical Preparation of Reduced Knoevenagel Adducts Using CO as a Deoxygenative Agent

A highly efficient one-step Rh-catalyzed preparation of reduced Knoevenagel adducts of various aldehydes and ketones with active methylene compounds has been developed. The protocol does not require an external hydrogen source and employs carbon monoxide as a deoxygenative agent. The use of malonic acid or cyanoacetamide enabled efficient formal deoxygenative addition of methyl acetate or acetonitrile to aldehydes. The developed methodology was applied to the synthesis of the precursors of biomedically important compounds.