Ruthenium carbenes as catalysts in stereoselective ene-yne metathesis/Diels-Alder and ene-yne metathesis/Diels-Alder/cross coupling multicomponent reactions

An ene-yne cross metathesis of silyl substituted alkynes and alkenes followed by a Diels-Alder reaction of the metathesis product 2-silyl-1,3-dienes has been developed. The dienes thus prepared in situ were shown to participate in highly diastereoselective Diels-Alder reactions. In one case the silicon substituted Diels-Alder cycloadduct was subsequently used without isolation and purification in a Hiyama cross coupling reaction. The cross coupling reactions enable these silicon dienes to be used as synthons for a variety of other dienes.