Article ID Journal Published Year Pages File Type
1346380 Tetrahedron: Asymmetry 2011 8 Pages PDF
Abstract

The reaction of the chiral nitrone MiPNO (2-isopropyl-2,3-dimethyl-1-oxy-2,3-dihydro-imidazol-4-one) with Grignard reagents is totally diastereoselective. Using simple and functionalized arylmagnesium reagents, enantiopure hydroxylamines were obtained in fair to good yields, which in turn could be easily transformed into new chiral ketonitrones. The preparation of enantiopure l-phenylglycine derivatives is also described.

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(2R,5R)-5-Biphenyl-4-yl-1-hydroxy-2-isopropyl-2,3-dimethyl-imidazolidin-4-oneC20H24N2O2>98% ee[α]D25=-123.9 (c 0.96, acetone)Source of chirality: (R)-2-isopropyl-2,3-dimethyl-1-oxy-2,3-dihydro-imidazol-4-oneAbsolute configuration: (2R,5R)

(2R,5R)-1-Hydroxy-2-isopropyl-2,3-dimethyl-5-pentafluorophenyl-imidazolidin-4-oneC14H15F5N2O2>98% ee[α]D25=+14.8 (c 0.94, acetone)Source of chirality: (R)-2-isopropyl-2,3-dimethyl-1-oxy-2,3-dihydro-imidazol-4-oneAbsolute configuration: (2R,5R)

(2R,5R)-1-Hydroxy-5-(4-methoxycarbonylphenyl)-2-isopropyl-2,3-dimethylimidazolidin-4-oneC16H22N2O4>98% ee[α]D25=-82.9 (c 1.00, acetone)Source of chirality: (R)-2-isopropyl-2,3-dimethyl-1-oxy-2,3-dihydro-imidazol-4-oneAbsolute configuration: (2R,5R)

(2R,5R)-1-Hydroxy-2-isopropyl-5-(4-methoxy-phenyl)-2,3-dimethyl-imidazolidin-4-oneC15H22N2O3>98% ee[α]D25=-104.1 (c 1.04, acetone)Source of chirality: (R)-2-isopropyl-2,3-dimethyl-1-oxy-2,3-dihydro-imidazol-4-oneAbsolute configuration: (2R,5R)

(2R,5R)-1-Hydroxy-2-isopropyl-2,3-dimethyl-5-p-tolyl-imidazolidin-4-oneC15H22N2O2>98% ee[α]D25=-115.0 (c 1.00, acetone)Source of chirality: (R)-2-isopropyl-2,3-dimethyl-1-oxy-2,3-dihydro-imidazol-4-oneAbsolute configuration: (2R,5R)

(2R,5R)-1-Hydroxy-2-isopropyl-2,3-dimethyl-5-phenyl-imidazolidin-4-oneC14H20N2O2>98% ee[α]D25=-108.2 (c 0.98, acetone)Source of chirality: (R)-2-isopropyl-2,3-dimethyl-1-oxy-2,3-dihydro-imidazol-4-oneAbsolute configuration: (2R,5R)

(2S,5S)-1-Hydroxy-2-isopropyl-5-(2-methoxy-phenyl)-2,3-dimethyl-imidazolidin-4-oneC15H22N2O3>98% ee[α]D25=+61.7 (c 1.04, acetone)Source of chirality: (S)-2-isopropyl-2,3-dimethyl-1-oxy-2,3-dihydro-imidazol-4-oneAbsolute configuration: (2S,5S)

(2R,5R)-5-(4-Dimethylamino-phenyl)-1-hydroxy-2-isopropyl-2,3-dimethyl-imidazolidin-4-oneC16H25N3O2>98% ee[α]D25=-111.3 (c 1.10, acetone)Source of chirality: (R)-2-isopropyl-2,3-dimethyl-1-oxy-2,3-dihydro-imidazol-4-oneAbsolute configuration: (2R,5R)

(2R,5R)-1-Hydroxy-2-isopropyl-2,3-dimethyl-5-thiophen-2-yl-imidazolidin-4-oneC12H18N2O2S>98% ee[α]D25=-64.9 (c 1.24, acetone)Source of chirality: (R)-2-isopropyl-2,3-dimethyl-1-oxy-2,3-dihydro-imidazol-4-oneAbsolute configuration: (2R,5R)

(2R,5R)-5-(4-Bromo-phenyl)-1-hydroxy-2-isopropyl-2,3-dimethyl-imidazolidin-4-oneC14H19BrN2O2>98% ee[α]D25=-106.9 (c 1.38, acetone)Source of chirality: (R)-2-isopropyl-2,3-dimethyl-1-oxy-2,3-dihydro-imidazol-4-oneAbsolute configuration: (2R,5R)

(2R,5R)-1-Hydroxy-5-(4-iodo-phenyl)-2-isopropyl-2,3-dimethyl-imidazolidin-4-oneC14H19IN2O2>98% ee[α]D25=-104.8 (c 1.14, acetone)Source of chirality: (R)-2-isopropyl-2,3-dimethyl-1-oxy-2,3-dihydro-imidazol-4-oneAbsolute configuration: (2R,5R)

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