Approaches to the Synthesis of the Vancomycin Antibiotics. Synthesis of Orienticin C (Bis-dechlorovancomycin) Aglycon

In the preceding paper, we described the synthesis of the vancomycin-related M(4-6)(5-7) bicyclic subunit 3 (Scheme 1),1,2 a structural motif common to all members of this family of antibiotics exemplified by vancomycin aglycon (1).3 Herein we describe the first synthesis of the vancomycin-related heptapeptide nucleus and the transformation of this intermediate to orienticin C (bis-dechlorovancomycin) aglycon (2).4