New highly efficient aziridine-functionalized tridentate sulfinyl catalysts for enantioselective diethylzinc addition to carbonyl compounds

New tridentate enantiomerically pure heteroorganic catalysts, containing hydroxyl, sulfinyl, and aziridine moieties, have proven to be highly efficient in the enantioselective diethylzinc addition to aryl and alkyl aldehydes to give the desired products in very high yields (up to 99%) and with ee’s up to 97%. The influence of the stereogenic centers located on the sulfinyl sulfur atom and in the aziridine moiety on the stereochemical course of the reaction are discussed.

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(RS)-2-Hydroxymethylphenyl 2′-[1-(2,2-dimethyl)aziridinyl]methylphenyl sulfoxideC18H21NO2SEe >99%[α]D = −1.8 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (RS) (literature data)

(RS,SC)-2-Hydroxymethylphenyl 2′-[1-(2-isopropyl)aziridinyl]methylphenyl sulfoxideC19H22NO2SEe >99%[α]D = +2.3 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (RS,SC) (literature data)

(RS,RC)-2-Hydroxymethylphenyl 2′-[1-(2-isopropyl)aziridinyl]methylphenyl sulfoxideC19H22NO2SEe >99%[α]D = −2.0 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (RS,RC) (literature data)

(RS,SC)-2-Hydroxymethylphenyl 2′-[1-(2-methyl)aziridinyl]methylphenyl sulfoxideC17H19NO2SEe >99%[α]D = +3.5 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (RS,SC) (literature data)