Functionalised carbocycles from carbohydrates. Part 3. The synthesis of the epoxy lactone prostaglandin intermediate via an isoxazolidine derivative. X-Ray crystal structure of (1R,5R)-6-exo,7-endo-dibenzoyloxy-8-exo-iodo-3-oxo-2-oxabicyclo[3.3.0]octane

Abstract

The bicyclic isoxazolidine 6,7-dibenzoyloxy-N-methyl-8-tosyloxy-3-oxa-2-azabicyclo[3.3.0]octane (1), which is easily obtained from a readily available D-glucose derivative, has been converted into the epoxy lactone 8-oxo-3,7-dioxatricyclo[4.3.0.0^2,4]nonane (13), via a series of cyclopentane derivatives, in ten steps. Since the product (13) can be used to prepare prostaglandins this sequence represents a new route to these compounds in their enantiomerically pure natural form.