Axially chiral C2-symmetric N-heterocyclic carbene (NHC) palladium complexes-catalyzed asymmetric arylation of aldehydes with arylboronic acids

Chiral C2-symmetric N-heterocyclic carbene (NHC) palladium diaquo complexes 5a–c and the chiral C2-symmetric NHC-palladium complexes 5d and 5e prepared from (R)-BINAM or H8-(R)-BINAM could be used as the catalysts for the enantioselective arylation of arylaldehydes with arylboronic acids in which NHC-Pd complex 5a was found to be fairly effective in this reaction to give the corresponding adducts in moderate enantioselectivities along with moderate to good yields.

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Cationic NHC-Pd(II) diaquo complex 5aC38H30F6N4O8PdS2Ee = 100%[α]D20=+43.0 (c 0.315, CHCl3)Source of chirality: resolutionAbsolute configuration: (R)

NHC-Pd(II) complex 5eC40H34F6N4O4PdEe = 100%[α]D20=+54.0 (c 0.162, CHCl3)Source of chirality: resolutionAbsolute configuration: (R)

(S)-(4-Nitrophenyl)(phenyl)methanolC13H11NO3Ee = 48%[α]D20=+14.0 (c 1.715, CHCl3)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration: (S)

(+)-(4-Nitrophenyl)(o-tolyl)methanolC14H13NO3Ee = 10%[α]D20=+6.8 (c 1.06, CHCl3)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration has not been determined.

(+)-(4-Nitrophenyl)(m-tolyl)methanolC14H13NO3Ee = 21%[α]D20=+13.5 (c 0.24, CHCl3)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration has not been determined

(+)-(4-Nitrophenyl)(p-tolyl)methanolC14H13NO3Ee = 23%[α]D20=+11.1 (c 1.03, CHCl3)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration has not been determined

(+)-Naphthalen-2-yl(4-nitrophenyl)methanolC17H13NO3Ee = 48%[α]D20=+2.0 (c 0.58 CHCl3)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration has not been determined

(+)-Biphenyl-4-yl(4-nitrophenyl)methanolC19H15NO3Ee = 57%[α]D20=+65.0 (c 0.35 CHCl3)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration has not been determined

(−)-Naphthalen-2-yl(3-nitrophenyl)methanolC17H13NO3Ee = 20%[α]D20=-87.0 (c 0.215, CHCl3)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration has not been determined

(+)-Biphenyl-4-yl(3-nitrophenyl)methanolC19H15NO3Ee = 29%[α]D20=+8.0 (c 0.35, CHCl3)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration has not been determined

(+)-4-(Biphenyl-4-yl(hydroxy)methyl)benzonitrileC20H15NOEe = 20%[α]D20=+7.8 (c 0.50, CHCl3)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration has not been determined

(S)-(2,4-Dichlorophenyl)(phenyl)methanolC13H10Cl2OEe = 65%[α]D20=-4.6 (c 0.91, acetone)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration: (S)

(−)-(2,4-Dichlorophenyl)(o-tolyl)methanolC14H12Cl2OEe = 20%[α]D20=-4.6 (c 0.75, CHCl3)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration has not been determined

(+)-(2,4-Dichlorophenyl)(m-tolyl)methanolC14H12Cl2OEe = 50%[α]D20=+3.6 (c 1.95, CHCl3)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration has not been determined

(+)-(2,4-Dichlorophenyl)(p-tolyl)methanolC14H12Cl2OEe = 40%[α]D20=+1.0 (c 0.50, CHCl3)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration has not been determined

(−)-Biphenyl-4-yl(2,4-dichlorophenyl)methanolC19H14Cl2OEe = 40%[α]D20=-5.6 (c 1.19, CHCl3)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration has not been determined

(−)-Biphenyl-4-yl(4-methoxyphenyl)methanolC20H18O2Ee = 1%[α]D20=-1.0 (c 0.24, CHCl3)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration has not been determined

(+)-Biphenyl-4-yl(2-chlorophenyl)methanolC19H15ClOEe = 6%[α]D20=+1.8 (c 0.78, CHCl3)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration has not been determined

(S)-(2-Chlorophenyl)(phenyl)methanolC13H11ClOEe = 13%[α]D20=+3.0 (c 0.15, CHCl3)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration: (S)

(+)-Biphenyl-4-yl(2-nitrophenyl)methanolC19H15NO3Ee = 5%[α]D20=+2.4 (c 0.545, CHCl3)Source of chirality: asymmetric arylation of aldehydesAbsolute configuration has not been determined