Asymmetric synthesis of the polyol subunit of the macrolide antibiotic, ossamycin: A unique approach utilizing stereochemical specificity

An asymmetric synthesis of the C1-C16 polyol subunit 2 of the macrolide antibiotic ossamycin (1) has been achieved through stepwise carbon-chain elongation reaction from D-glucose, based on a chiral pool approach. An outstanding point of this strategy is asymmetric induction by utilizing steric hindrance of neighboring groups. The stereogenic centers at the C4 and C5 positions of 2 were constructed by mCPBA epoxidation, and the C6 and C7 positions of 2 were produced by catalytic OsO4 dihydroxylation under highly stereoselective conditions.