Organocatalytic asymmetric aza-Michael addition of aniline to chalcones under solvent-free conditions

The first enantioselective Michael addition of aniline to chalcones was promoted by cheap and commercially available chincona alkaloids under solvent-free conditions. Variously substituted chalcones were examined as substrates giving the conjugate adducts in moderate to good enantioselectivity. The simple experimental procedure had no work-up and short reaction times, which are the notable advantages.

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(R)-3-(3-Methoxyphenyl)-1-phenyl-3-(phenylamino)propan-1-oneC22H21NO2Ee = 40%[α]D32=-12.5 (c 0.5, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (3R)

(R)-1-Phenyl-3-(phenylamino)-3-p-tolylpropan-1-oneC22H21NOEe = 42%[α]D32=+3.9 (c 0.5, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (3R)

(R)-1-(4-Methoxyphenyl)-3-phenyl-3-(phenylamino)propan-1-oneC22H21NO2Ee = 49%[α]D32=-5.7 (c 0.5, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (3R)

(R)-3-Phenyl-3-(phenylamino)-1-p-tolylpropan-1-oneC22H21NO2Ee = 52%[α]D32=-16.0 (c 0.5, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (3R)

(R)-1-(4-Chlorophenyl)-3-phenyl-3-(phenylamino)propan-1-oneC21H18ClNOEe = 31%[α]D32=-5.8 (c 0.55, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (3R)