Stereodivergent Resolution of Oxabicyclic Ketones: Preparation of Key Intermediates for Platensimycin and Other Natural Products

An
improved methodology for the preparation of enantiopure oxabicyclo[3.2.1]­octadienes
via a stereodivergent resolution is reported. High catalyst control
proximal to the oxabridged stereocenter produces readily separable
diastereomers in high yield (>92%) and with excellent optical purity
(>95% ee). This resolution strategy is amenable to large-scale
preparations,
and the utility of the resolution was further demonstrated in the
asymmetric preparation of a key intermediate used in the synthesis
of the antibiotic (−)-platensimycin.