Highly enantioselective direct conjugate addition of ketones to nitroalkenes promoted by a chiral primary amine-thiourea catalyst.
Primary amine-thiourea derivative 1 is an active and highly enantioselective catalyst for the conjugate addition of ketones to nitroalkenes. Broad substrate scope is described, with nitroalkenes bearing either aromatic or aliphatic substituents and a wide variety of ketones shown to be useful reacting partners. Ethyl ketones react preferentially, generating anti products with methyl-bearing stereocenters with good-to-excellent diastereoselectivity. An enamine mechanism is indicated, with cooperative activation of the electrophile by the thiourea and of the ketone by the primary amine.
Huang
Hongbing
H
Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA.
Jacobsen
Eric N
EN
D000475:Alkenes / Q000138:chemical synthesis* / Q000737:chemistry; D000588:Amines / Q000737:chemistry; D002384:Catalysis; D007659:Ketones / Q000737:chemistry*; D015394:Molecular Structure; D009574:Nitro Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D013890:Thiourea / Q000031:analogs & derivatives*
D000475:Alkenes; D000588:Amines; D007659:Ketones; D009574:Nitro Compounds; D013890:Thiourea