Synthesis of Long‐Chain Sugars by Iterative, Diastereoselective Homologation of 2,3‐O‐Isopropylidene‐D‐glyceraldehyde with 2‐Trimethylsilylthiazole

D‐Aldoses with up to nine C atoms have been synthesized stepwise by homologation of the glyceraldehyde derivative 1. The two key steps are the anti diastereoselective addition of 2 to an α‐chiral aldehyde and the conversion of the thiole ring in the adduct into the formyl group. The reaction sequence 1+2→3→4 illustrates the principle of the reaction. (Figure Presented.)