Remote 1,5-stereoinduction in boron aldol reactions of methyl ketones: application to the convergent assembly of the 1,3-polyol sequence of (+)-roxaticin

By exploiting 1,5-anti stereoinduction in the boron aldol coupling of the β-alkoxy methyl ketones 6 and 8 with aldehydes 7 and 9, the convergent synthesis of 2, corresponding to the fully protected polyol sequence of the 30-membered macrolide, (+)-roxaticin (1), was achieved in an efficient manner (15 steps and 24.0% yield from ketone 15).