Developing molecular diversity in the construction of a family of bicyclic isoxazolines scaffolds: Control of regio-and diastereoselectivities

A completely regioselective approach to bicyclic isoxazolines has been found starting from 4-cyclopentene-1,3-dione or 2-cyclopentenones. 1,3-Dipolar cycloaddn. with nitrile oxides gave different semirigid bicyclic scaffolds with at least four points of elaboration for mol. diversity. From these intermediates, two families of regioisomer isoxazolines can be prepd. with complete control of their relative stereochem. Further elaboration of functional groups was demonstrated in order to exploit a successive parallel prepn. of arrays of compds. Crystal structure of some of these products were also reported