Enantioselective Strecker-type reaction of phosphinoyl ketimines catalyzed by a chiral Zr-bipyridyldiol catalyst

An enantioselective Strecker reaction of N-diphenylphosphinoyl ketimines with TMSCN employing a chiral zirconium complex formed from chiral bipyridyl diol 1 as catalyst is described. The catalytic efficiency of chiral ligand 1 with other Lewis acids was also explored. Higher yields (50–85%) with moderate to good enantioselectivities (30–80%) were achieved for a variety of N-diphenylphosphinoyl ketimines.

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N-[1-Cyano-1-(2-methoxyphenyl)ethyl]diphenylphosphinic amideC22H21N2O2P[α]D23=-2.15 (c 1.3, CH2Cl2)

N-[1-Cyano-1-(3-methoxyphenyl)ethyl]diphenylphosphinic amideC22H22N2O2P[α]D23=-4.9 (c 1.6, CH2Cl2)

N-[1-Cyano-1-(4-methoxyphenyl)ethyl]diphenylphosphinic amideC22H22N2O2P[α]D23=-2.35 (c 0.85, CH2Cl2)

N-[1-Cyano-1-(2-methylphenyl)ethyl]diphenylphosphinic amideC22H21N2OP[α]D23=-2.7 (c 2.0, CH2Cl2)

N-[1-Cyano-1-(3-methylphenyl)ethyl]diphenylphosphinic amideC22H21N2OP[α]D23=-1.7 (c 1.05, CH2Cl2)

N-[1-Cyano-1-(4-methylphenyl)ethyl]diphenylphosphinic amideC22H21N2OP[α]D23=-1.7 (c 1.05, CH2Cl2)

N-[1-(2-Bromophenyl)-1-cyanoethyl]diphenylphosphinic amideC21H18BrN2OP[α]D23=-1.3 (c 1.15, CH2Cl2)

N-[1-(3-Bromophenyl)-1-cyanoethyl]diphenylphosphinic amideC21H18BrN2OP[α]D23=-4.6 (c 1.4, CH2Cl2)

N-[1-(4-Bromophenyl)-1-cyanoethyl]diphenylphosphinic amideC21H18BrN2OP[α]D23=-6.4 (c 1.15, CH2Cl2)

N-[1-(3-Chlorophenyl)-1-cyanoethyl]diphenylphosphinic amideC21H18ClN2OP[α]D23=-3.2 (c 1.25, CH2Cl2)

N-[1-(4-Chlorophenyl)-1-cyanoethyl]diphenylphosphinic amideC21H18ClN2OP[α]D23=-5.7 (c 0.85, CH2Cl2)

N-Cyano(phenyl)methyl(diphenyl)phosphinic amideC20H17N2OP[α]D23=-0.6 (c 1.2, CH2Cl2)

N-(1-Cyano-1-phenylpropyl)diphenylphosphinic amideC22H21N2OP[α]D23=+0.9 (c 1.2, CH2Cl2)

N-(1-Cyano-1-phenylbutyl)diphenylphosphinic amideC23H23N2OP[α]D23=-3.4 (c 0.85, CH2Cl2)

N-(1-Cyano-2-methyl-1-phenylpropyl)diphenylphosphinic amideC23H23N2OP[α]D23=-3.2 (c 1.05, CH2Cl2)

N-[1-Cyano-1-(1-naphthyl)ethyl]diphenylphosphinic amideC25H21N2OP[α]D23=-1.2 (c 1.25, CH2Cl2)

N-[1-Cyano-1-(2-naphthyl)ethyl]diphenylphosphinic amideC25H21N2OP[α]D23=-3.2 (c 1.05, CH2Cl2)

N-[1-Cyano-1-(2-furyl)ethyl]diphenylphosphinic amideC19H17N2O2P[α]D23=-2.7 (c 0.9, CH2Cl2)

N-[1-Cyano-1-(3-thienyl)ethyl]diphenylphosphinic amideC19H17N2OPS[α]D23=-0.9 (c 1.05, CH2Cl2)

N-[1-Cyano-1-(3-pyridyl)ethyl]diphenylphosphinic amideC20H18N3OP[α]D23=-2.4 (c 1.05, CH2Cl2)