Determination of the absolute configuration of bicyclo[3.3.1]nonane-2,7-dione by circular dichroism spectroscopy and chemical correlation

A study of the enantiomers of bicyclo[3.3.1]nonane-2,7-dione, a chiral mole cule containing two carbonyl chromophores, was performed. Enantiomers of th is structure were obtained by HPLC resolution and the (+)-(1R,5S)-enantiome r by enantiospecific synthesis from(+)-(1S,5S)-bicyclo[3.3.1]nonane-2,6-dio ne. The title structure is an interesting molecule to demonstrate the valid ity of the octant rule. The location of the major chair-chair conformer int o octants placing each chromophore into the origin of the octants. led to t he opposite configuration assignments. In order to prove unequivocally abso lute configuration, enantiospecific synthesis of the title compound was car ried out. The kinetic resolution of racemic bicyclo [3.3.1] nonane-2,6-dion e using baker's yeast afforded (+)-(1S,5S)-2,6-dione. Employing a reaction sequence analogous to one developed earlier by us. with racemic substrates led to carbonyl group shift giving enantiomerically pure (+)-(1R,5S)-bicycl o [3.3.1]nonane-2,7-dione. The absolute configuration of the investigated c ompound was established by combined use of the octant rule and chemical cor relation. (C) 2001 Wiley-Liss, Inc.