generate the desired 20‐membered macrolactam. This second‐generation strategy made it possible to prepare synthetic analogues of vicenistatin, including the C20‐ and/or C23‐demethyl analogues. Evaluation of the cytotoxic effect of these analogues indicated the importance of the fixed conformation of aglycon for determining the biological activity of the vicenistatins.
A highly convergent total synthesis of macrocyclic lactam glycoside vicenistatin is described. Key features of the synthesis include rapid assembly of the macrolactam part and macrocyclic ring closure via intramolecular Stille coupling.
Enantioselective total synthesis of an antitumor antibiotic, vicenistatin, featuring a 20-membered macrocyclic lactam glycoside with the amino sugar vicenisamine, has been achieved. Key reactions in the synthesis of macrolactam aglycone involved Suzuki cross-coupling and Evans asymmetric aldol reaction. Penultimate glycosidation of the O-TMS-aglycone with appropriately protected 1-O-acetyl amino sugar and final deprotection allowed accomplishment of the total synthesis.