Synthesis of the Pluramycins 1: Two Designed Anthrones as Enabling Platforms for Flexible Bis-C-Glycosylation

Two effective tricyclic platforms are reported for the installation of the two constituent sugars, L-vancosamine and D-angolosamine, in a regio- and stereoselective manner for the synthesis of the pluramycin class of bis-C-glycoside antitumor antibiotics. Two complementary protocols are now available that differ in the order in which the two sugar moieties are installed. Sc(OTf)(3) was effective as the Lewis acid.