Asymmetric addition of trimethylsilyl cyanide to aldehydes promoted by chiral polymeric vanadium(V) salen complex as an efficient and recyclable catalyst

The asymmetric addition of trimethylsilyl cyanide to various aldehydes catalyzed by efficient new vanadyl polymeric salen complexes having 12 repeating salen units was investigated at room temperature. An excellent yield of the trimethylsilylether of cyanohydrins (up to 98%) with high chiral induction (96%) in case of 2-methylbenzaldehyde was achieved in 18 h. The catalyst recovered four times with retention of its performance.

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poly[(R,R-(−)-N,N′-bis-{3-(1,1-methyl)-5-methylene salicylidine}-cyclohexene-1,2-diamine vanadium(V)] ethylsulphateC25H31N2O8SV+[α]D27=-591 (c 0.05, CH2Cl2)Source of chirality: (1R,2R)-diaminocyclohexaneAbsolute configuration: (1R,2R)

poly[(R,R-(−)-N,N′-bis-{3-(1,1-dimethylethyl)-5-methylene salicylidine}-cyclohexene-1,2-diamine vanadium(V)] ethylsulphateC31H43N2O8SV+[α]D27=-204.6 (c 0.05, CH2Cl2)Source of chirality: (1R,2R)-diaminocyclohexaneAbsolute configuration: (1R,2R)

(S)-2-O-Acetyl-2-phenyl acetonitrileC10H9NO2Ee = 94%[α]D27=-31.5 (c 1, CH2Cl2)Source of chirality: (1R,2R)-diaminocyclohexaneAbsolute configuration: S

(S)-2-O-Acetyl-2-(2-methoxyphenyl) acetonitrileC11H11NO3Ee = 89%[α]D27=-25.6 (c 1, CH2Cl2)Source of chirality: (1R,2R)-diaminocyclohexaneAbsolute configuration: S

(S)-2-O-Acetyl-2-(4-flourophenyl) acetonitrileC10H8FNO2Ee = 80%[α]D27=-20.2 (c 1, CH2Cl2)Source of chirality: (1R,2R)-diaminocyclohexaneAbsolute configuration: S

(S)-2-O-Acetyl-2-(4-methoxyphenyl) acetonitrileC11H11NO3Ee = 86%[α]D27=-24.4 (c 1, CH2Cl2)Source of chirality: (1R,2R)-diaminocyclohexaneAbsolute configuration: S

(S)-2-O-Acetyl-2-(2-methylphenyl) acetonitrileC11H11NO2Ee = 96%[α]D27=-26.2 (c 1, CH2Cl2)Source of chirality: (1R,2R)-diaminocyclohexaneAbsolute configuration: S

(S)-2-O-Acetyl-2-(3-methoxyphenyl) acetonitrileC11H11NO3Ee = 82%[α]D27=-23.1 (c 1, CH2Cl2)Source of chirality: (1R,2R)-diaminocyclohexaneAbsolute configuration: S

(S)-2-O-Acetyl-2-(4-chlorophenyl) acetonitrileC10H8ClNO2Ee = 77%[α]D27=-10.2 (c 1, CH2Cl2)Source of chirality: (1R,2R)-diaminocyclohexaneAbsolute configuration: S

(S)-2-O-Acetyl-2-(4-bromophenyl) acetonitrileC10H8BrNO2Ee = 79%[α]D27=-11.6 (c 1, CH2Cl2)Source of chirality: (1R,2R)-diaminocyclohexaneAbsolute configuration: S