Asymmetric Michael addition of N-boc-protected oxindoles to nitroalkenes catalyzed by a chiral secondary amine.

New mission for prolinol ethers: A secondary-amine-catalyzed Michael addition of N-Boc-protected oxindoles to nitroalkenes through a Brønsted base activation mode has been developed, furnishing the products in excellent yields (88-98 %), diastereoselectivities (d.r.=98:2->99:1) and high to excellent enantioselectivities (82->99 % ee; see scheme).