Contiguously substituted cyclooctane polyols. Configurational assignments via H-1 NMR correlations and symmetry considerations

摘要

More advanced oxidation of the cyclooctadienol shown, readily available in enantiomerically pure form from D-glucose, has given rise to a series of intermediates whose relative (and ultimately absolute) configuration was assigned on the basis of H-1/H-1 coupling constant analysis. The selectivities that were deduced in this manner were drawn from the sequential application of CrO3 oxidation in tandem with Luche reduction, two-step NMO-promoted osmylations bracketed by acetonide formation, and wholesale deprotection. The stereoselectivities of these reactions were traced by H-1 NMR spectroscopy, and the stereochemical assignments were confirmed by the presence or absence of symmetry in the final cyclooctane polyols (four shown) generated in this investigation.