A Stereoselective Total Synthesis of (9S)-9-Dihydroerythronolide A via Coupling between the Right-Half (C1-C6) Aldehyde and the Left-Half (C7-C15) Sulfoxide

As part of a study directed at the total synthesis of (9S)-9-dihydroerythronolide A, the C7-C15 sulfoxide, (2S, 3R, 4S, 5R, 6R, 7R)-3, 5-isopropylidenedioxy-7-(4-methoxybenzyloxy)-6-methoxymethoxy-1-phenylsulfinyl-2, 4, 6-trimethylnonane, was coupled with the C1-C6 aldehyde, (2R, 3S, 4S, 5R)-6-tert-butyldiphenylsilyloxy-3, 5-dimethyl-2, 4-isopropylidenedioxyhexanal, to give the C1-C15 hydroxysulfoxide, which was converted to the seco-acid via a stereocontrolled methylation at the C6 position. Macrocyclization of the seco-acid by Yamaguchi's method gave the 14-membered lactone, which was converted to (9S)-9-dihydroerythronolide A.