Enantioselective Cascade Reaction of -Cyano Ketones and Isatylidene Malononitriles: Asymmetric Construction of Spiro[4H-pyran-oxindoles]

摘要

-Cyano ketones have been employed for the first time as Michael donors in the construction of chiral spiro compounds. By using only 2 mol-% of a chiral multifunctional organocatalyst, chiral spiro[4H-pyran-oxindole] derivatives were prepared in yields of 97-99% with enantioselectivities of 76-97%ee. This method provides a new approach to the synthesis of chiral spirocyclic oxindoles.