On the stereochemistry of the olefinic double bond in 13-membered heterocyclic rings accessible by ring-closing metathesis reaction

13-Membered heterocyclic ring analogs of the core structure of manzamine alkaloids were synthesized by ring closing metathesis (RCM) reaction. The influence of a remote heteroatom (N, O, S) on E/Z stereochemistry of the olefinic double bond formed in RCM reaction using Grubbs 1st and 2nd generation ruthenium carbene complexes was evaluated. Studies show that RCM reaction is kinetically controlled and the hetero atoms influence the double bond stereochemistry.