ASYMMETRIC SYNTHESIS OF OCTAHYDROBENZOFURAN CORE STRUCTURE WITH THREE CONTIGUOUS STEREOGENIC CENTERS AND DEVELOPMENT OF THE ABSOLUTE CONFIGURATIONS

摘要

Cyclization of enantiopure (S/R)-1 with halogen-reagent-constructed enantiopure octahydrobenzofuran core structure with contiguous three stereogenic centers of both enantiomers (SRR and RSS). The absolute configurations of all compounds have been established from x-ray analysis of the single crystal of (3aS,7aR,7R)-3. The chiral initiation in diastereoselective mode of 5-exo ring closure across C/C bond of pendant cyclohexene moiety has been proposed.