A gold-catalyzed 1,2-acyloxy migration/intramolecular cyclopropanation/ring enlargement cascade: syntheses of medium-sized heterocycles.

The synthesis of medium-sized heterocycles possessing a trans double bond is still a challenge. Herein, gold(I)-catalyzed 1,2-acyloxy migration/intramolecular cyclopropanation/ring enlargement cascade reaction of furans has been developed, providing highly efficient access to ten- and eleven-membered heterocycles with a broad substrate scope under mild reaction conditions. The reaction outcome features high chemoselectivity at the C5-position of furan. Moreover, a trans-double bond was embodied in the medium ring system.