Organocatalytic asymmetric desymmetrization: efficient construction of spirocyclic oxindoles bearing a unique all-carbon quaternary stereogenic center via sulfa-Michael addition.

An unprecedented enantioselective desymmetrization of spiro cyclohexadienone oxindoles has been developed successfully via organocatalyzed asymmetric SMA, which provides facile access to spirocyclic oxindoles bearing a unique all-carbon quaternary stereogenic center with excellent levels of stereoselectivity.