A Paradigm Case for the Merging of Glycal and Enzymatic Assembly Methods in Glycoconjugate Synthesis: A Highly Efficient Chemo‐Enzymatic Synthesis of GM3

A concise, regio‐ and stereoselective synthesis of the ganglioside GM3 has been achieved. Use of an α‐1,2‐oxirane derived from lactal facilitated installation of the anomeric β‐ceramide side chain. Introduction of the sialic acid residue at C3, of the lactose was accomplished regiospecifically by enzymatically mediated sialyl transfer from CMP‐Neu‐5‐Ac.