Stereoselective convergent total synthesis of tonkinelins

Abstract

We report the stereoselective synthesis of (17S,18S,36S)-tonkinelin and its diastereomer (17R,18R,36S)-tonkinelin via a convergent strategy involving the stepwise construction of two key fragments: a chiral ester-derived phosphonium salt and a requisite aldehyde for a convergent Wittig olefination. Key transformations in the sequence include asymmetric dihydroxylation, Wittig olefination, ring-closing metathesis (RCM) and chemoselective diimide olefin reduction. The synthesized tonkinelins were fully characterized, and their spectroscopic data were found to be consistent with previously reported data.