Comparison of CD Spectra of (2-Methylphenyl)- and (2,6-Dimethylphenyl)-phenylmethanols Leads to Erroneous Absolute Configurations

Enantiopure (2,6-dimethylphenyl)phenylmethanol (+)-( 3 ) and analog (+)-( 4 ) were prepared and their CD spectra were found opposite to that of (2-methylphenyl)phenylmethanol ( R )-( m )-( 2 ), the absolute configuration of which was previously established by X-ray crystallography. Therefore the S absolute configuration was once assigned to (+)- 3 and (+)- 4 . After that we have succeeded in the X-ray analyses of chiral dichlorophthalate esters of (+)- 3 and (+)- 4 , which clearly indicated R absolute configuration. It is thus evident that comparison of the CD spectra of alcohols 2 , 3 , and 4 leads to erroneous absolute configurations.

Keywords:

• ( R )-(−)-(2-methylphenyl)phenylmethanol
• ( R )-(+)-(2,6-dimethylphenyl)phenylmethanol
• ( R )-(+)-(2,4,6-trimethylphenyl)phenylmethanol
• Chiral Dichlorophthalic Acid
• Enantioresolution
• Hplc Separation
• X-ray Crystallography
• Absolute Configuration