Highly enantioselective 1,4-addition of arylzinc reagents to 3-arylpropenals catalyzed by a rhodium–binap complex in the presence of chlorotrimethylsilane

Asymmetric 1,4-addition of arylzinc chlorides to (E)-3-arylpropenals proceeded with high enantioselectivity in the presence of a rhodium/(R)-binap catalyst and chlorotrimethylsilane to give, after hydrolysis, high yields of the corresponding 3,3-diarylpropanals of 98–99% ee. The presence of the chlorosilane is essential for high yields of the 1,4-addition products.

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(S)-3-(4-Methoxyphenyl)-3-phenylpropanalC16H16O2Ee = 99%[α]D20=+4.4 (c 0.77, CHCl3)Source of chirality: asymmetric arylationAbsolute configuration: (S)

(S)-3-(2-Methoxyphenyl)-3-phenylpropanalC16H16O2Ee = 99%[α]D20=-54.3 (c 1.4, CHCl3)Source of chirality: asymmetric arylationAbsolute configuration: (S)

(S)-3-(2-Methoxy-5-methylphenyl)-3-phenylpropanalC17H18O2Ee = 99%[α]D20=-16.2 (c 1.4, CHCl3)Source of chirality: asymmetric arylationAbsolute configuration: (S)

(S)-3-(4-Fluorophenyl)-3-phenylpropanalC15H13FOEe = 98%[α]D20=+3.3 (c 1.8, CHCl3)Source of chirality: asymmetric arylationAbsolute configuration: (S)

(R)-3-(4-Methoxyphenyl)-3-phenylpropanalC16H16O2Ee = 99%[α]D20=-4.2 (c 0.80, CHCl3)Source of chirality: asymmetric arylationAbsolute configuration: (R)

(R)-3-(3-Methoxyphenyl)-3-phenylpropanalC16H16O2Ee = 99%[α]D20=-0.5 (c 1.9, CHCl3)Source of chirality: asymmetric arylationAbsolute configuration: (R)

(R)-3-(3,5-Dimethylphenyl)-3-phenylpropanalC17H18OEe = 99%[α]D20=-6.2 (c 1.6, CHCl3)Source of chirality: asymmetric arylationAbsolute configuration: (R)

(R)-3-(2-Naphthyl)-3-phenylpropanalC19H16OEe = 99%[α]D20=-36.9 (c 2.0, CHCl3)Source of chirality: asymmetric arylationAbsolute configuration: (R)

(R)-3-(4-Chlorophenyl)-3-phenylpropanalC15H13ClOEe = 99%[α]D20=-5.7 (c 2.0, CHCl3)Source of chirality: asymmetric arylationAbsolute configuration: (R)

(R)-3-(3-Chlorophenyl)-3-phenylpropanalC15H13ClOEe = 98%[α]D20=-4.9 (c 1.6, CHCl3)Source of chirality: asymmetric arylationAbsolute configuration: (R)