Preparation of Axially Chiral Biphenyls by Configuration Transformation Based on Chiral Amino Alcohols

Axially chiral biphenyls (P, S)-3a and (M, R)-3b were obtained from (M/P)-4,4'-dimethoxy-5,6,5',6'-bis(methylenedioxy)-2-carboxylester-2'-carboxamide biphenyls via configuration transformation of the biphenyls with (S)-alaninol or (R)-alaninol chiral-arm. Crystal structure of (P, 5)-3a was determined. The crystal of (P, S)-3a belongs to monoclinic, space group P2(1), a=12.122(2) angstrom, b=8.9911(18) angstrom, c=12.779(3) angstrom, beta=112.38(3)degrees. There are two kinds of hydrogen-bonding in the (P. S)-3a crystal. The first is hydrogen-bonding between the hydroxyl group of the amino alcohol arm and the amide oxygen of a neighboring molecule. The second is hydrogen-bonding between the amide hydrogen atom and the amide oxygen of a neighboring molecule. Each molecule is linked to its two adjacent molecules by four intermolecular H-bonds. The configuration of (M, R)-3b was assigned based on the CD spectra. In addition, from (P, S)-3a, (P)-2,2'-dihydroxymethyl-4,4'-dimethoxy-5,6,5',6'-bis(methylenedioxy)-biphenyl (6a) was synthesized.