Divergent syntheses of (−)-carvone-derived dimers

Abstract

A series of diterpene-type compounds were synthesized starting from commercially available (−)-carvone. The Michael reaction of (−)-carvone itself delivered four diastereomeric dimers divergently. Following in parallel transformations of reduction, condensation and reductive amination, the corresponding alcohol, oxime and amine were obtained respectively. Particularly, several cage-like structures were obtained via late-stage olefin functionalization. The absolute configurations of the aforementioned compounds were unambiguously determined by NMR spectral, X-ray crystallographic and conformational analysis. Finally, the in-vitro anti-cancer and anti-inflammatory activities of these dimers were tested preliminarily.