Carbonylation approaches to oxygen heterocyclic compounds

Reactions of 3-(3',4',6'-tri-O-benzyl-beta-D-glucopyranosyl)propene with H- 2/CO in the presence of rhodium catalysts can give high yields of a linear aldehyde which can be further modified to give fused 6,7-oxygen heterocycli c compounds. These are useful as intermediates in the synthesis of cyclic p olyethers, e.g., the marine toxin, ciguatoxin CTX1. Almost complete regiose lectivity for the linear aldehyde was obtained using the bulky bidentate di phosphite ligand, BIPHEPHOS. (C) 1999 Elsevier Science B.V. All rights rese rved.