Chirality in Abundance: A Reagent-Controlled Access to Multiple Stereoisomers of Functionalized Bishomocubanes

Efficient access to enantiopure polycyclic cage compounds
is a
challenging but attractive objective. The 1,3-bishomocubane (BHC)
skeleton, in particular, is distinguished by its chirality, exceptional
configurational and conformational rigidity, and unique 3D structure.
Herein, we report the enantioselective synthesis of all possible isomers
of a bishomocubyl amino alcohol. This was accomplished by using Ellman’s
sulfinamide as a chiral resolving agent (CRA) and tuning the reaction
conditions. Thus, treatment of a racemic bishomocubyl ketoalcohol,
possessing eight fixed chiral centers, with both enantiomers of Ellmann
sulfinamide led to all possible (eight) isomers of sulfinamide, which
on hydrolysis afforded four stereoisomers (two pairs of enantiomers)
of enantiomerically pure amino alcohols. Possible application of such
enantiopure functionalized cage compounds as chiral ligands and catalysts
has also been demonstrated.