Model studies directed to the synthesis of cucurbitacin I C/D rings

Herein, we detail a synthetic strategy toward the C/D rings of cucurbitacin I, a naturally occurring triterpenoid. This route utilized ring-opening/ring-closing metathesis of a norbornene derivative for the formation of the C/D ring advanced intermediates, allowing for stereocontrol of the chiral centers. (C) 2015 Elsevier Ltd. All rights reserved.