Alternative Syntheses of the C9-C15 and C1-C5 Segments of Erythronolide A via Regio- and Stereo-Selective Reductive Ring Opening of 2, 3-Epoxy Alcohols

Improved syntheses are described of two segments required for the total synthesis of (9S)-9-dihydroerythronolide. A, i.e., (2S, 3R, 4S, 5R)-2, 4-dimethyl-5-(4-methoxybenzyloxy)heptane-1, 3, 4-triol corresponding to the C9-C15 subunit and (2S, 3R, 4R)-5-benzyloxy-2, 3-dimethylpentane-1, 4-diol corresponding to the C1-C5 subunit, via regio- and stereo-selective reduction of 2, 3-epoxy alcohols.