Catalytic, asymmetric Strecker reactions catalysed by titaniumIV and vanadiumV(salen) complexes

VanadiumV(salen) complex 3 has been found to be an effective catalyst for the asymmetric addition of hydrogen cyanide (generated in situ from trimethylsilyl cyanide) to imines. The best results (up to 81% enantiomeric excess) were obtained for aromatic imines in which the nitrogen atom is protected with a benzyl group and in which the imine bond is not sterically encumbered.

Figure optionsDownload as PowerPoint slide

(R)-2-Benzylamino-phenylacetonitrileC15H14N2Ee = 75%[α]D20=+64.0 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)

(S)-2-Benzylamino-(4-methylphenyl)acetonitrileC16H16N2Ee = 70%[α]D20=-32.2 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(S)-2-Benzylamino-(3-methylphenyl)acetonitrileC16H16N2Ee = 74%[α]D20=-58.0 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(S)-2-Benzylamino-(2-methylphenyl)acetonitrileC16H16N2Ee = 52%[α]D20=-72.1 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(S)-2-Benzylamino-(2-naphthyl)acetonitrileC19H16N2Ee = 72%[α]D20=-4.0 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(S)-2-Benzylamino-(1-naphthyl)acetonitrileC19H16N2Ee = 34%[α]D20=-112.0 (c 0.5, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(R)-2-Benzylamino-(3-methoxyphenyl)acetonitrileC16H16N2OEe = 59%[α]D20=+25.9 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)

(S)-2-Benzylamino-(4-methoxyphenyl)acetonitrileC19H16N2OEe = 72%[α]D20=-12.0 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(R)-2-Benzylamino-(3-chlorophenyl)acetonitrileC15H13N2ClEe = 57%[α]D22=+2.4 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)

(S)-2-Benzylamino-(4-chlorophenyl)acetonitrileC15H13N2ClEe = 41%[α]D20=-19.7 (c 0.8, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(S)-2-Benzylamino-(4-trifluoromethylphenyl)acetonitrileC16H13N2F3Ee = 31%[α]D20=-28.3 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(S)-2-Benzylamino-3,3-dimethylbutanonitrileC13H18N2Ee = 16%[α]D20=-29.3 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(R)-2-Benzylamino-2-phenyl-propanonitrileC16H16N2Ee = 43%[α]D21=+16.6 (c 0.5, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)

(S)-2-Allylamino-phenylacetonitrileC11H12N2Ee = 31%[α]D22=-65.5 (c 0.5, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)