Fluorous derivatives of (1R,2R)-diaminocyclohexane as chiral ligands for metal-catalyzed asymmetric reactions

Perfluoroalkyl-substituted, enantiopure diamines derived from (1R,2R)-diaminocyclohexane were conveniently prepared from readily available precursors. In situ generated metal complexes of these ligands were tested as chiral catalysts in three standard asymmetric reactions (cyclopropanation of styrene, hydrogen transfer reduction of acetophenone, and allylic alkylation of 1,3-diphenyl-2-propenyl acetate) affording enantioselectivities of up to 47% in the copper-catalyzed cyclopropanation of styrene.

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(1R,2R)-N,N′-Bis(1H,1H-perfluorooctyl)-cyclohexane-1,2-diamineC22H16F30N2Ee = 100%[α]D20=-27.1 (c 0.2, Et2O)Source of chirality: (1R,2R)-diaminocyclohexaneAbsolute configuration: (1R,2R)

(1R,2R)-N,N′-Bis(1H,1H,2H,2H-perfluorodecyl)-cyclohexane-1,2-diamineC26H20F34N2Ee = 100%[α]D20=-28.1 (c 0.2, CH3OH)Source of chirality: (1R,2R)-diaminocyclohexaneAbsolute configuration: (1R,2R)

(1R,2R)-N,N′-Bis(1H,1H,2H,2H,3H,3H-perfluoroundecyl)-cyclohexane-1,2-diamineC28H24F34N2Ee = 100%[α]D20=-29.5 (c 0.2, Et2O)Source of chirality: (1R,2R)-diaminocyclohexaneAbsolute configuration: (1R,2R)

(1R,2R)-N,N′-Bis(1H,1H,2H,2H-perfluorododecyl)-cyclohexane-1,2-diamineC30H28F34N2Ee = 100%[α]D20=-27.1 (c 0.2, CH3OH)Source of chirality: (1R,2R)-diaminocyclohexaneAbsolute configuration: (1R,2R)