Enantiomer separation and absolute configuration of densely functionalized 2-oxatricyclo[4.3.1.03,8]decanes by CD spectroscopy and chemical correlation

Enantiomer separation by HPLC on a swollen microcrystalline triacetylcellulose column of highly substituted 2-oxatricyclo[4.3.1.0(3,8)]decane (2-oxaprotoadamantane) structures afforded enantiomers of this molecule. Application of the octant rule to the carbonyl chromophore to establish the absolute configuration of the enantiomers did not lead to an unequivocal conclusion. The enantioselective synthesis of 4-bromo-3-methoxy-oxaprotoadamantanone was performed from homochiral (+)-(1S,5S)-bicyclo[3.3.1]nonane-2,6-dione thus permitting the assignment of the (1R,3S,4S,6R,8R)-configuration to the title structures. (C) 2000 Elsevier Science Ltd. All rights reserved.