Bis-TADDOLs as bifunctional organocatalysts for trifluoromethylation of aldehydes and ring-opening of cyclohexene oxide with p-toluidine

A set of bis-TADDOLs, in which two TADDOL moieties are connected by different linkers, have been prepared. A great dependence of the catalytic activities of the bis-TADDOLs on the distance between the TADDOL moieties was found by the addition of trifluoromethyltrimethylsilane to benzaldehyde and ring-opening of cyclohexene oxide with or without alkali metal salts added.

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((4R,4′R,5R,5′R)-2,2′-(1,2-Phenylene)bis(1,3-dioxolane-5,4,2-triyl))tetrakis(diphenylmethanol)C64H54O8[α]D25=+100 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R,R)

((4R,4′R,5R,5′R)-2,2′-(1,3-Phenylene)bis(1,3-dioxolane-5,4,2-triyl))tetrakis(diphenylmethanol)C64H54O8[α]D25=+22 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R,R)

((4R,4′R,5R,5′R)-2,2′-(1,4-Phenylene)bis(1,3-dioxolane-5,4,2-triyl))tetrakis(diphenylmethanol)C64H54O8[α]D25=+68 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R,R)

((4R,4′R,5R,5′R)-2,2′-(Methylenebis(4,1-phenylene))bis(1,3-dioxolane-5,4,2-triyl))tetrakis(di(phenyl)methanol)C71H60O8[α]D25=+43.1 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R,R)

((4R,4′R,5R,5′R)-2,2′-(1,4-Phenylene)bis(1,3-dioxolane-5,4,2-triyl))tetrakis(di(naphthalen-2-yl)methanol)C96H70O8[α]D25=+204 (c 1, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R,R)