Stereoselective synthesis of advanced intermediates en route to Taxuspine U and X: a study of macrocyclization via ring closing metathesis to highly constrained twelve-membered rings

The stereoselective synthesis of an advanced intermediate of Taxuspine U and X has been accomplished using a ring closing metathesis strategy. The feasibility of ring closing metathesis in synthesizing highly constrained and functionalized macrocycles has been demonstrated provided the appropriate substrate structure and substitution pattern are chosen.