Synthesis of Cortistatins A, J, K and L

Abstract

We considered it likely that one or more pathways linking the azido alcohol 5 to the cyclohexadienone 6 could be developed. The oxabicyclic core of the latter precursor could then be disconnected by an oxidative cyclization transform, a strategy independently conceived and previously demonstrated by Sarpong and coworkers, as well as others. 8,15,16,18 To allow for a convergent assembly process, we imagined an earlier disconnection of the seven-membered B-ring by an olefin metathesis reaction, giving rise to the triene precursor 7, which we envisioned could be synthesized by coupling of the o-