Asymmetric cyanohydrin formation from aldehydes catalyzed by manganese Schiff base complexes

The catalyst generated in situ from Mn(OAc)2 and a chiral Schiff base ligand exhibited excellent catalytic abilities in asymmetric cyanohydrin formation from aldehydes with sodium cyanide in up to 99% enantioselectivity and good yield.

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(R)-2-Hydroxy-2-(naphthalen1yl)acetonitrileC12H9NOEe = 99% (by chiral HPLC)[α]D20=+38.1 (c 1.00, CHCl3)20Source of chirality: (1R,2R)-(−)-1,2-diaminocyclohexaneAbsolute configuration: (R)

(R,E)-2-Hydroxypent-3-enenitrileC5H7NOEe = 12% (by chiral HPLC)[α]D20=-4.8 (c 1.00, CHCl3)23Source of chirality: (1R,2R)-(−)-1,2-diaminocyclohexaneAbsolute configuration: (R)

(R)-2-Hydroxy-2-phenyacetonitrileC8H7NOEe = 98% (by chiral GC)[α]D20=+42.0 (c 1.00, CHCl3)16Source of chirality: (1R,2R)-(−)-1,2-diaminocyclohexaneAbsolute configuration: (R)

(R)-2-Hydroxy-3-phenylpropanenitrileC9H9NOEe = 74% (by chiral HPLC)[α]D20=+8.8 (c 2.75, CHCl3)16Source of chirality: (1R,2R)-(−)-1,2-diaminocyclohexaneAbsolute configuration:(R)

(R)-2-Hydroxy-2-(pyridin-2-yl)acetonitrileC7H6N2OEe = 95% (by chiral HPLC)[α]D20=+2.6 (c 0.10, CHCl3)Source of chirality: (1R,2R)-(−)-1,2-diaminocyclohexaneAbsolute configuration: (R)

(R)-2-(4-Fluorophenyl)-2-hydroxyacetonitrileC8H6FNOEe = 83% (by chiral HPLC)[α]D20=+31.5 (c 1.40, CHCl3)7bSource of chirality: (1R,2R)-(−)-1,2-diaminocyclohexaneAbsolute configuration: (R)

(R)-2-Hydroxy-2-p-tolylacetonitrileC9H9NOEe = 97% (by chiral HPLC)[α]D20=+50.4 (c 1.00, CHCl3)7bSource of chirality: (1R,2R)-(−)-1,2-diaminocyclohexaneAbsolute configuration: (R)

(R)-2-Hydroxy-2-(4-methoxyphenyl)acetonitrileC9H9NO2Ee = 91% (by chiral HPLC)[α]D20=+41.7 (c 2.00, CHCl3)24Source of chirality: (1R,2R)-(−)-1,2-diaminocyclohexaneAbsolute configuration: (R)

(R)-2-(4-Chlorophenyl)-2-hydroxyacetonitrileC8H6ClNOEe = 99% (by chiral HPLC)[α]D20=+40.2 (c 1.00, CHCl3)7bSource of chirality: (1R,2R)-(−)-1,2-diaminocyclohexaneAbsolute configuration: (R)

(R)-2-Hydroxy-2-(4-nitrophenyl)acetonitrileC8H6N2O3Ee = 99% (by chiral GC)[α]D20=+15.1 (c 1.40, CHCl3)17Source of chirality: (1R,2R)-(−)-1,2-diaminocyclohexaneAbsolute configuration: (R)

(R)-2-(4-Bromophenyl)-2-hydroxyacetonitrileC8H6BrNOEe = 99% (by chiral HPLC)[α]D23=+14.5 (c 1.03, CHCl3)22Source of chirality: (1R,2R)-(−)-1,2-diaminocyclohexaneAbsolute configuration: (R)

(R)-2-Hydroxy-2-(3-methoxyphenyl)acetonitrileC9H9NO2Ee = 89% (by chiral HPLC)[α]D22=+36.2 (c 1.35, CHCl3)24Source of chirality: (1R,2R)-(−)-1,2-diaminocyclohexaneAbsolute configuration: (R)

(R)-2-(2-Chlorophenyl)-2-hydroxyacetonitrileC8H6ClNOEe = 81% (by chiral HPLC)[α]D22=-3.0 (c 0.92, CHCl3)20Source of chirality: (1R,2R)-(−)-1,2-diaminocyclohexaneAbsolute configuration: (R)

(R)-2-Hydroxy-2-(2-nitrophenyl)acetonitrileC8H6N2O3Ee = 66% (by chiral HPLC)[α]D25=+73.9 (c 1.00, CHCl3)21Source of chirality: (1R,2R)-(−)-1,2-diaminocyclohexaneAbsolute configuration:(R)