Asymmetric Synthesis of the α-d-Galactosyl Ceramide KRN7000 via an Organocatalytic Aldol Reaction as Key Step

Abstract

The asymmetric synthesis of the antitumor and immunostimulatory α-d-galactosyl ceramide KRN7000 using a (R)-proline-catalyzed enantioselective aldol reaction as key step is described. The title compound is synthesized in thirteen linear steps with excellent stereoselectivity (de >98%, ee = 95%) employing the commercially available substrates 1-pentadecanal, 2,2-dimethyl-1,3-dioxan-5-one, hexacosanoic acid, and d-galactose.