Chiral synthesis of polyketide-derived natural products. Part 4. Synthesis of a left-hand segment with six consecutive chiral centres of dihydroerythronolide A for the total synthesis of erythromycin A from D-glucose

Abstract

For the purpose of the total synthesis of erythromycin A (1) from D-glucose (2) with the aid of stereochemical control in acyclic systems and p-methoxyphenylmethyl (MPM) protection, (2R,3S,4S,5R,6R,7R)-1-hydroxy-5,6-isopropylidenedioxy-3,7-bis(4-methoxybenzyloxy)-2,4,6-trimethylnonane (55), a left-hand segment corresponding to the C-7—C-15 segment of 9-dihydroerythronolide A, was synthesiszed from D-glucose (2) through some stereoselective reactions in open-chain sytems, e.g. the Wittig reaction, OsO4 oxidation, and epoxidation.