Synthesis of vinyldihydropyran by cooperative catalysis

Abstract

Delta(5)-Unsaturated aldehydes with a suitably positioned allylic halide, or phosphate, leaving group undergo doubly-catalyzed cyclization to give dihydropyran derivatives. The cyclization proceeds under the synergetic action of diazabicycloundecene and Pd(PPh3)(4). This type of transformation was also accomplished with an aryl ketone.