Parallel kinetic resolution of active esters using a quasi-enantiomeric combination of (R)-4-phenyl-oxazolidin-2-one and (S)-4,5,5-triphenyl-oxazolidin-2-one

The parallel kinetic resolution of a series of racemic pentafluorophenyl 2-(4-aryl/phenyl)-propionates and -butanoates using a quasi-enantiomeric combination of (R)-4-phenyl-oxazolidin-2-one and (S)-4,5,5-triphenyl-oxazolidin-2-one is discussed. The levels of diastereoselectivity were excellent (86–98% de) leading to separable quasi-enantiomeric oxazolidin-2-one adducts in good yield. This methodology was used to resolve 2-phenyl propionic acid.

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(2S,4R)-3-(2-Phenylpropionyl)-4-phenyl-oxazolidin-2-oneC18H17NO3De >98%; ee >98%[α]D20=+92.5 (c 4.9, CHCl3)Source of chirality: chiral poolAbsolute configuration: (S,R)

(2S,4R)-3-[2-(4-Methylphenyl)propionyl]-4-phenyl-oxazolidin-2-oneC19H19NO3De >98%; ee >98%[α]D20=+121.6 (c 0.6, CHCl3)Source of chirality: chiral poolAbsolute configuration: (S,R)

(2S,4R)-3-[2-(4-Isobutylphenyl)propionyl]-4-phenyl-oxazolidin-2-oneC22H25NO3De >98%; ee >98%[α]D20=+118.7 (c 6.0, CHCl3)Source of chirality: chiral poolAbsolute configuration: (S,R)

(2S,4R)-3-[2-(4-Chlorophenyl)propionyl]-4-phenyl-oxazolidin-2-oneC18H16ClNO3De >98%; ee >98%[α]D20=+144.4 (c 1.6, CHCl3)Source of chirality: chiral poolAbsolute configuration: (S,R)

(2S,4R)-3-(2-Phenylbutanoyl)-4-phenyl-oxazolidin-2-oneC19H19NO3De >98%; ee >98%[α]D20=+77.4 (c 4.0, CHCl3)Source of chirality: chiral poolAbsolute configuration: (S,R)

(2S,4R)-3-(2-Phenyl-3-methylbutanoyl)-4-phenyl-oxazolidin-2-oneC20H21NO3De = 54%; ee >98%[α]D20=+1.3 (c 3.0, CHCl3)Source of chirality: chiral poolAbsolute configuration: (S,R)

(2R,4S)-3-(2-Phenylpropionyl)-4,5,5-triphenyl-oxazolidin-2-oneC30H25NO3De = 96%; ee >98%[α]D20=-255.1 (c 3.4, CHCl3)Source of chirality: chiral poolAbsolute configuration: (R,S)

(2R,4S)-3-[2-(4-Methylphenyl)propionyl]-4,5,5-triphenyl-oxazolidin-2-oneC31H27NO3De = 96%; ee >98%[α]D20=-258.6 (c 2.4, CHCl3)Source of chirality: chiral poolAbsolute configuration: (R,S)

(2R,4S)-3-[2-(4-Isobutylphenyl)propionyl]-4,5,5-triphenyl-oxazolidin-2-oneC34H33NO3De = 96%; ee >98%[α]D20=-306.7 (c 4.4, CHCl3)Source of chirality: chiral poolAbsolute configuration: (R,S)

(2R,4S)-3-[2-(4-Chlorophenyl)propionyl]-4,5,5-triphenyl-oxazolidin-2-oneC30H24ClNO3De = 92%; ee >98%[α]D20=-296.2 (c 3.4, CHCl3)Source of chirality: chiral poolAbsolute configuration: (R,S)

(2R,4S)-3-(2-Phenylbutanoyl)-4,5,5-triphenyl-oxazolidin-2-oneC31H27NO3De = 94%; ee >98%[α]D20=-195.2 (c 3.4, CHCl3)Source of chirality: chiral poolAbsolute configuration: (R,S)

(2R,4S)-3-(2-Phenyl-3-methylbutanoyl)-4,5,5-triphenyl-oxazolidin-2-oneC32H29NO3De = 76%; ee >98%[α]D20=-270.9 (c 2.6, CHCl3)Source of chirality: chiral poolAbsolute configuration: (R,S)

(2S,4R)-3-[2-(6-Methoxynaphth-2-yl)-propionyl]-4,5,5-triphenyl-oxazolidin-2-oneC35H29NO4De = 92%; ee >98%[α]D20=+302.5 (c 1.2, CHCl3)Source of chirality: chiral poolAbsolute configuration: (S,R)

(2S,4R)-3-[2-(6-Methoxynaphth-2-yl)-propionyl]-4-phenyl-oxazolidin-2-oneC23H21NO4De = 98%; ee >98%[α]D20=+207.5 (c 0.8, CHCl3)Source of chirality: chiral poolAbsolute configuration: (S,R)

(S)-2-Phenylpropionic acidC9H10O2Ee >95%[α]D20=+71.7 (c 1.0, CHCl3)Source of chirality: resolutionAbsolute configuration: (S)