New ferrocenyl P,S and S,S ligands for asymmetric catalysis

Various new chiral ferrocenyl phosphine-thioethers and thiophosphine-thioethers with planar chirality only have been efficiently synthesized with good overall yields (39–43%) in enantiomerically pure form by a nine-step sequence involving the introduction of the planar chirality by Kagan’s acetal method. These new P,S and S,S ligands have been successfully used in the palladium-catalyzed asymmetric allylic substitution reaction (ee up to 93%).

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(S)-2-Thiodiphenylphosphino-(tert-butylthiomethyl)ferroceneC27H29FePS2[α]D = +76.0 (c 0.5, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(S)-2-Thiodiphenylphosphino-(isopropylthiomethyl)ferroceneC26H27FePS2[α]D = +25.6 (c 0.5, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(S)-2-Thiodiphenylphosphino-(ethylthiomethyl)ferroceneC25H25FePS2[α]D = +44.5 (c 0.5, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(S)-2-Thiodiphenylphosphino-(cyclohexylthiomethyl)ferroceneC29H31FePS2[α]D = −77.6 (c 0.5, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(S)-2-Thiodiphenylphosphino-(benzylthiomethyl)ferroceneC30H27FePS2[α]D = −17.1 (c 0.5, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)

(S)-2-Thiodiphenylphosphino-(phenylthiomethyl)ferroceneC29H25FePS2[α]D = −39.5 (c 0.5, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)