Direct, catalytic enantioselective nitroaldol (Henry) reaction of trifluoromethyl ketones: an asymmetric entry to alpha-trifluoromethyl-substituted quaternary carbons.
Herein we describe the first direct, catalytic enantioselective nitroaldol (Henry) reaction of simple alpha-trifluoromethyl ketones with nitromethane using a chiral monometallic lanthanum(III) triflate salt complex, namely [(Delta,S,S,S)-Binolam]3.La(OTf)3, as enantioselective catalyst. The resulting alpha-trifluoromethyl tertiary nitroaldols were obtained in moderate to high yields (up to 93%) and enantioselectivities (up to 98% ee). These adducts are versatile chiral building blocks and may be reduced (NiCl2/NaBH4) to their beta-amino-alpha-trifluoromethyl tertiary alcohols without loss of enantiomeric purity.
Tur
Fernando
F
Departament de Química, Universitat de les Illes Balears, 07122 Palma de Mallorca, Spain.
Saá
José M
JM
D002384:Catalysis; D018360:Crystallography, X-Ray; D007659:Ketones / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009566:Nitrates / Q000737:chemistry; D009574:Nitro Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D007659:Ketones; D009566:Nitrates; D009574:Nitro Compounds; C421036:methyl nitrate