Asymmetric hydrogenation and allylic substitution reaction with novel chiral pinene-derived N,P-ligands

A series of new chiral tetrahydroquinoline ligands, derived from chiral α-pinene, were successfully synthesized. Iridium and palladium complexes of these ligands were proven to be efficient catalysts for enantioselective hydrogenation and allylic substitution reactions with moderate to excellent enantioselectivities (90–95% ee) and high yields.

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(5R,7S,8S)-6,6-Dimethyl-8-diphenylphosphinoborane-5,6,7,8-tetrahydro-2-phenyl-5,7-methanoquinolineC30H31BNPEe = 100%[α]D20=+118 (c 0.72, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,7S,8S)

(5R,7S,8S)-6,6-Dimethyl-8-di-o-tolylphosphinoborane-5,6,7,8-tetrahydro-2-phenyl-5,7-methanoquinolineC32H35BNPEe = 100%[α]D20=-19.1 (c 1.2, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,7S,8S)

(5R,7S,8S)-6,6-Dimethyl-8-di-p-tolylphosphinoborane-5,6,7,8-tetrahydro-2-phenyl-5,7-methanoquinolineC32H35BNPEe = 100%[α]D20=+58.9 (c 0.56, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,7S,8S)

(5R,7S,8S)-8-Bis(2-methoxyphenyl)phosphinoborane-6,6-dimethyl-5,6,7,8-tetrahydro-2-phenyl-5,7-methanoquinolineC32H35BNO2PEe = 100%[α]D20=-23.8 (c 0.55, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,7S,8S)

(5R,7S,8S)-8-Bis(4-methoxyphenyl)phosphinoborane-6,6-dimethyl-5,6,7,8-tetrahydro-2-phenyl-5,7-methanoquinolineC32H35BNO2PEe = 100%[α]D20=+72 (c 0.72, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,7S,8S)

(5R,7S,8S)-8-Dicyclohexylphosphinoborane-6,6-dimethyl-5,6,7,8-tetrahydro-2-phenyl-5,7-methanoquinolineC30H43BNPEe = 100%[α]D20=+17.8 (c 1.0, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,7S,8S)

(5R,7S,8S)-8-Bis(3,5-bistrifluoromethylphenyl)phosphinoborane-6,6-dimethyl-5,6,7,8-tetrahydro-2-phenyl-5,7-methanoquinolineC34H27BF12NPEe = 100%[α]D20=-61.3 (c 0.72, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,7S,8S)

(η4-1,5-Cyclooctadiene)[(5R,7S,8S)-6,6-dimethyl-8-diphenylphosphine-5,6,7,8-tetrahydro-2-phenyl-5,7-methanoquinoline] iridium(I) tetrakis[3,5-bis(trifluoromethyl)phenyl]borateC70H52BF24IrNPEe = 100%[α]D20=+100.8 (c 1.05, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,7S,8S)

(η4-1,5-Cyclooctadiene)[(5R,7S,8S)-6,6-dimethyl-8-di-o-tolylphosphine-5,6,7,8-tetrahydro-2-phenyl-5,7-methanoquinoline] iridium(I) tetrakis[3,5-bis(trifluoromethyl)phenyl]borateC72H56BF24IrNPEe = 100%[α]D20=+148.9 (c 0.68, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,7S,8S)

(η4-1,5-Cyclooctadiene)[(5R,7S,8S)-6,6-dimethyl-8-di-p-tolylphosphine-5,6,7,8-tetrahydro-2-phenyl-5,7-methanoquinoline] iridium(I) tetrakis[3,5-bis(trifluoromethyl)phenyl]borateC72H56BF24IrNPEe = 100%[α]D20=+102.3 (c 0.9, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,7S,8S)

(η4-1,5-Cyclooctadiene)[(5R,7S,8S)-8-bis(2-methoxyphenyl)phosphine-6,6-dimethyl-5,6,7,8-tetrahydro-2-phenyl-5,7-methanoquinoline] iridium(I) tetrakis[3,5-bis(trifluoromethyl)phenyl]borateC72H56BF24IrNPEe = 100%[α]D20=63.0 (c 0.9, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,7S,8S)

(η4-1,5-Cyclooctadiene)[(5R,7S,8S)-8-bis(4-methoxyphenyl)phosphine-6,6-dimethyl-5,6,7,8-tetrahydro-2-phenyl-5,7-methanoquinoline] iridium(I) tetrakis[3,5-bis(trifluoromethyl)phenyl]borateC72H56BF24IrNO2PEe = 100%[α]D20=+94.7 (c 0.35, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,7S,8S)

(η4-1,5-Cyclooctadiene)[(5R,7S,8S)-8-dicyclohexylphosphine-6,6-dimethyl-5,6,7,8-tetrahydro-2-phenyl-5,7-methanoquinoline] iridium(I) tetrakis[3,5-bis(trifluoromethyl)phenyl]borateC70H64BF24IrNPEe = 100%[α]D20=-27.3 (c 1.36, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,7S,8S)

(η4-1,5-Cyclooctadiene)[(5R,7S,8S)-8-bis(3,5-bis(trifluoromethyl)phenyl)phosphine-6,6-dimethyl-5,6,7,8-tetrahydro-2-phenyl-5,7-methanoquinoline] iridium(I) tetrakis[3,5-bis(trifluoromethyl)phenyl]borateC74H48BF36IrNPEe = 100%[α]D20=-34.1 (c 0.4, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,7S,8S)