trans-(2R,3R)-2,3-Diphenylcyclopropane-1,1-dimethanol: a pivotal diol for the synthesis of novel C2-symmetric ligands for asymmetric transition metal catalysis

Various chiral ligands bearing phosphorus or nitrogen donor atoms were obtained in a straightforward manner starting from trans-(2R,3R)-diphenylcyclopropane-1,1-dimethanol as a key structure. These chiral ligands were tested and compared in palladium(0)-catalyzed asymmetric allylic alkylation reactions (up to 71% ee) and rhodium(I)-catalyzed asymmetric hydrogenations (up to 88% ee). Moreover, in the asymmetric allylic alkylation, we observed excellent activity with a diphosphinite ligand (TOF = 600 mol 17 × [mol Pd × h)−1].

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(2R,3R)-2,3-Diphenylcyclopropane-1,1-dimethanolC17H18O2[α]D20=-118.9 (c 1.0, CHCl3)Source of chirality: Sharpless asymmetric dihydroxylationAbsolute configuration: (2R,3R)

(2R,3R)-1,1-bis[(Diphenylphosphanyl)methylene]-2,3-diphenylcyclopropaneC41H36P2[α]D20=+108.8 (c 1.0, CH2Cl2)Source of chirality: Sharpless asymmetric dihydroxylationAbsolute configuration: (2R,3R)

{[(2R,3R)-2,3-Diphenylcyclopropane-1,1-diyl]bis(methylene)}-bisdiphenylphosphiniteC41H36O2P2[α]D20=+15.6 (c 1.0, CH2Cl2)Source of chirality: Sharpless asymmetric dihydroxylationAbsolute configuration: (2R,3R)

(2R,3R)-1,1-bis-(Benzylideneaminomethyl)-2,3-diphenylcyclopropaneC31H28N2[α]D20=-22.1 (c 1.0, DMSO)Source of chirality: Sharpless asymmetric dihydroxylationAbsolute configuration: (2R,3R)

(2R,3R)-1,1-bis-[(2,6-Dichlorobenzylidene)aminomethyl]-2,3-diphenylcyclopropaneC31H24Cl4N2[α]D20=-69.3 (c 1.0, DMSO)Source of chirality: Sharpless asymmetric dihydroxylationAbsolute configuration: (2R,3R)

(2R,3R)-1,1-bis-[(2,6-Dichlorobenzylamino)methyl]-2,3-diphenylcyclopropaneC31H28Cl4N2[α]D20=+17.5 (c 1.0, CHCl3)Source of chirality: Sharpless asymmetric dihydroxylationAbsolute configuration: (2R,3R)