The synthesis of oximes and nitroalkanes bearing a chiral auxiliary unit: convenient substrates for the preparation of enantiomerically pure nitrile oxides

We report the synthesis of four new oximes and three nitroalkanes bearing a chiral unit. All these compounds were converted into nitrile oxides and subjected to 1,3-dipolar cycloaddition with 3-E-hexene, giving the corresponding 2-isoxazolines in fair yields but only with moderate stereoselectivities.

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2-N-Glyoxyloyl-(2R)-bornane-10,2-sultam oximeC12H18N2O4S[α]D20 = −111 (c 1.02, CHCl3)Source of chirality: (2R)-bornane-10,2-sultam

2-N-Glyoxyloyl-7,7-dimethylnorbornane-(1S,2R)-oxazolidinone oximeC12H16N2O4[α]D20 = +102 (c 1.00, CHCl3)Source of chirality: 7,7-dimethylnorbornane-(1S,2R)-oxazolidinone

2-O-Glyoxyloyl-N,N-dicyclohexyl-10-sulfamoyl-(2R)-isobornane oximeC24H40N2O5S[α]D20 = −42.3 (c 1.0, CH2Cl2)Source of chirality: N,N-dicyclohexyl-10-sulfamoyl-(2R)-isobornane

O-Glyoxyloyl-(1R)-menthyl oximeC12H21NO3[α]D20 = −87.5 (c 1.0, CH2Cl2)Source of chirality: (1R)-menthol

O-Glyoxyloyl-(1R)-8-phenylmenthyl oximeC18H25NO3[α]D20 = −87 (c 1.2, CHCl3)Source of chirality: (1R)-8-phenylmenthol

2′-N-(2-Nitroethanoyl)-(2′R)-bornane-10′,2′-sultamC12H18N2O5S[α]D20 = −25 (c 0.96, CHCl3)Source of chirality: (2R)-bornane-10,2-sultam

2′-N-(2-Nitroethanoyl)-7′,7′-dimethylnorbornane-(1′S,2′R )-oxazolidinoneC12H16O6N2[α]D20 = +79(c 0.21, CHCl3)Source of chirality: 7,7-dimethylnorbornane-(1S,2R)-oxazolidinone

O-(2-Nitroethanoyl)-(1′R)-8′-phenylmentholC18H25O4N[α]D20 = +80 (c 1.24, CHCl3)Source of chirality: (1R)-8-phenylmenthol