A phosphine-catalyzed novel [4+2] annulation process was devised employing allene ketones as C-2 synthons and beta,gamma-unsaturated alpha-keto esters as C-4 synthons. In the presence of an L-threonine-derived bifunctional phosphine, 3,4-dihydropyrans were obtained in high yields and with virtually perfect enantioselectivities. The synthetic value of the dihydropyran motif was demonstrated by a concise preparation of an anti-hypercholesterolemic agent.