Enantioselective synthesis of functionalized medium-sized oxacycles.

Enantioselective routes to functionalized, seven-, eight-, and nine-membered oxacycles that are amenable to further elaboration have been developed. Salient features of the methodology include highly diastereoselective and regioselective transformations of an ephedrine-derived epoxy morpholinone to functionalized precursors of the oxacycles. The ephedrine scaffold exerts remote stereocontrol in the functionalization of the appended oxacycle. [reaction: see text]