Large-scale synthesis of the anti-cancer marine natural product (+)-discodermolide. Part 1: Synthetic strategy and preparation of a common precursor

The synthetic strategy for producing multigram quantities of (+)-discodermolide (1) using a hybridized Novartis-Smith-Paterson synthetic route via common precursor 3 is described. In the first part of this five-part series, we present a multikilogram preparation of alpha-methyl aldehyde 10 from Roche ester, its syn-aldol reaction with Evans boron enolate, removal of the chiral auxiliary, and the preparation of Weinreb amide 3 (Smith common precursor). The common precursor was produced without any chromatography.