Selective formation of dihydropyran derivatives by a tandem domino ring-closing metathesis/cross-metathesis

A ring-closing metathesis (RCM)/cross-metathesis (CM) domino reaction has been applied to esters and unsymmetrical ether prepared from 1,5-hexadien-3-ol. For the first time, dihydropyran derivatives have been obtained via a regioselective cyclization. This reaction was performed in high yield and E stereoselectivity.