Syntheses and resolutions of new chiral biphenyl backbones:: 2-amino-2′-hydroxy-6,6′-dimethyl-1,1′-biphenyl and 2-amino-2′-hydroxy-4,4′,6,6′-tetramethyl-1,1′-biphenyl

The new chiral backbones (R)-(+)- and S-(-)-2-amino-2'-hydroxy-6,6'-dimethyl-1,1'-biphenyl and (R)-(+)- and (S)- (-)2-amino-2'-hydroxy-4,4',6,6'-tetramethyl-1,1'-biphenyl were synthesized from o-methylaniline and 2,4-dimethyl-aniline respectively in seven steps. A new resolution method was developed to provide homochiral enantiomers (from diastereomeric salts) in reasonably high yields. The absolute configuration of the new biphenyls was confirmed by X-ray structural analysis. (C) 2003 Elsevier Science Ltd. All rights reserved.