Silver(I)-Catalyzed Intramolecular Cyclizations of Epoxide-Propargylic Esters to 1,4-Oxazine Derivatives.

An interesting silver(I)-catalyzed, one-pot intramolecular cyclization of epoxide-propargylic esters is described. A variety of 1,4-oxazine derivatives were obtained through a novel domino sequence, including three-membered ring-opening, 3,3-sigmatropic rearrangement, 6- exo -cycloisomerization and subsequent intramolecular elimination in moderate yields under mild conditions.