tert-Butanesulfinylthioether ligands: synthesis and application in palladium-catalyzed asymmetric allylic alkylation

A class of novel chiral SO–S-type bidentate ligands based on the tert-butylsulfinyl moiety as the sole chiral source were designed and synthesized through a simple and efficient pathway. These ligands are effective catalyst precursors for the palladium-catalyzed allylic alkylation of 1,3-diphenyl-2-propenyl acetate and moderate to good stereoselectivities (up to 84% ee) were obtained.

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(R)-(2-(tert-Butylsulfinyl) phenyl) (phenyl) sulfaneC16H18OS2[α]D20=+244.6 (c 0.8, CH2Cl2)Source of chirality: (R)-tert-butyl tert-butanethiosulfinateAbsolute configuration: (R)

(R)-(2-(tert-Butylsulfinyl) phenyl) (methyl) sulfaneC11H16OS2[α]D20=+286.3 (c 1.0, CH2Cl2)Source of chirality: (R)-tert-butyl tert-butanethiosulfinateAbsolute configuration: (R)

(R)-tert-Butyl (2-(tert-butylsulfinyl) phenyl) sulfaneC14H22OS2[α]D20=+191.4 (c 1.1, CH2Cl2)Source of chirality: (R)-tert-butyl tert-butanethiosulfinateAbsolute configuration: (R)

(R)-Benzyl (2-(tert-butylsulfinyl) phenyl) sulfaneC17H20OS2[α]D20=+207.3 (c 0.5, CH2Cl2)Source of chirality: (R)-tert-butyl tert-butanethiosulfinateAbsolute configuration: (R)

(R)-(2-(tert-Butylsulfinyl) phenyl) (naphthalene-1-ylmethyl) sulfaneC21H22OS2[α]D20=+269.3 (c 1.0, CH2Cl2)Source of chirality: (R)-tert-butyl tert-butanethiosulfinateAbsolute configuration: (R)

(R)-(2-(tert-Butylsulfinyl) phenyl) (2,4,6-trimethylbenzyl) sulfaneC20H26OS2[α]D20=+206.6 (c 1.0, CH2Cl2)Source of chirality: (R)-tert-butyl tert-butanethiosulfinateAbsolute configuration: (R)

(R)-Benzyl (2-(tert-butylsulfinyl)-3-methoxyphenyl) sulfaneC18H22O2S2[α]D20=+70.2 (c 1.5, CH2Cl2)Source of chirality: (R)-tert-butyl tert-butanethiosulfinateAbsolute configuration: (R)

(R)-Benzyl (2-(tert-butylsulfinyl)-6-methoxyphenyl) sulfaneC18H22O2S2[α]D20=-35.4 (c 0.8, CH2Cl2)Source of chirality: (R)-tert-butyl tert-butanethiosulfinateAbsolute configuration: (R)

(R)-Benzyl (2-(tert-butylsulfinyl)-6-isopropoxyphenyl) sulfaneC20H26O2S2[α]D20=-66.1 (c 0.7, CH2Cl2)Source of chirality: (R)-tert-butyl tert-butanethiosulfinateAbsolute configuration: (R)

(R)-Benzyl (2-(tert-butylsulfinyl)-6-(methoxymethoxy) phenyl) sulfaneC19H24O3S2[α]D20=-17.1 (c 0.7, CH2Cl2)Source of chirality: (R)-tert-butyl tert-butanethiosulfinateAbsolute configuration: (R)

(R)-Benzyl (2-(tert-butylsulfinyl)-3, 6-dimethoxyphenyl) sulfaneC19H24O3S2[α]D20=-15.3 (c 0.7, CH2Cl2)Source of chirality: (R)-tert-butyl tert-butanethiosulfinateAbsolute configuration: (R)

(S,E)-Dimethyl 2-(1,3-diphenylallyl) malonateC20H20O4[α]D20=-14.6 (c 0.7, EtOH) 84%eeSource of chirality: asymmetric synthesisAbsolute configuration: (S)

(S,E)-Diethyl 2-(1,3-diphenylallyl) malonateC22H24O4[α]D20=-15.5 (c 0.8, CHCl3) 81%eeSource of chirality: asymmetric synthesisAbsolute configuration: (S)

(S,E)-Dibenzyl 2-(1,3-diphenylallyl) malonateC32H28O4[α]D20=-7.2 (c 0.4, CHCl3) 74%eeSource of chirality: asymmetric synthesisAbsolute configuration: (S)

(E)-Ethyl 2-cyano-3,5-diphenylpent-4-enoateC20H18NO2[α]D20=-4.2 (c 0.3, CHCl3) 79%eeSource of chirality: asymmetric synthesisAbsolute configuration: undetermined