Total Synthesis of Lobatamides A and C

Abstract

AbstractThe total synthesis of lobatamides A (1 a) and C (1 c) via a common bislactone intermediate is reported. The allylic aryl moiety including a trisubstituted Z‐olefin was constructed by hydroboration of a 1,1‐disubstituted allene and subsequent Migita‐Kosugi‐Stille coupling. Although the seco acid proved to be highly unstable even in the presence of weak bases, Zhao macrolactonization under acidic conditions via the α‐acyloxyenamide successfully provided the common bislactone intermediate. Hydrozirconation‐iodination of the terminal alkyne and subsequent copper‐mediated coupling with primary amides proceeded successfully in the presence of the sensitive bislactone framework. The developed synthetic route enables the late‐stage installation of enamide side chains, which are crucial structures for V‐ATPase inhibition.