Synthesis of chiral 2,2′-dimethyl-1,1′-binaphthyl-8,8′-diamine and barriers of atropisomerization of the related binaphthyls

Chiral 2,2′-dimethyl-1,1′-binaphthyl-8,8′-diamine 3b was synthesized via a diastereomeric resolution and determination of the absolute configurations, and the barriers compared for atropisomerization amongst binaphthyl skeletons.

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(S)-2,2′-Dimethyl-1,1′-binaphthyl-8,8′-diamineC22H20N2[α]D20=-43 (c 0.5, CHCl3)Source of chirality: resolutionAbsolute configuration: (S)

(R)-2,2′-Dimethyl-1,1′-binaphthyl-8,8′-diamineC22H20N2[α]D20=+43 (c 0.50, CHCl3)Source of chirality: resolutionAbsolute configuration: (R)

(1R,2S,5R)-2-Isopropyl-5-methylcyclohexyl (S)-8′-amino-2,2′-dimethyl-1,1′-binaphthyl-8-ylcarbamateC33H38N2O2[α]D20=-103 (c 0.5, CHCl3)Source of chirality: resolutionAbsolute configuration: (1R,2S,5R)

(1R,2S,5R)-2-Isopropyl-5-methylcyclohexyl (R)-8′-amino-2,2′-dimethyl-1,1′-binaphthyl-8-ylcarbamateC33H38N2O2[α]D20=-109 (c 0.9, CHCl3)Source of chirality: resolutionAbsolute configuration: (1R,2S,5R)