Synthesis of 17-membered azalides from a 16-membered macrolide utilizing amide-selective silane reduction

The synthesis of 17-membered azalides was achieved using the following key steps: (i) Beckmann rearrangement of 16-membered oxime derivatives obtained from 3,4'-dideoxymycaminosyltylonolide (DDMT), (ii) amide-selective silane reduction of the corresponding ring-enlarged lactams catalyzed by RhCl3 in the presence of Et3N, and (iii) N-methylation of the resulting secondary amines.