Regio- and Stereoselective Syntheses of Isoxazolidines Bearing Phosphinyl Substituents

The 1,3-dipolar cycloaddition of nitrones to vinylphosphine derivatives gives valuable new phosphinyl- and phosphino-substituted isoxazolidines also in optically pure form. A complete study of the regioselectivity and stereoselectivity of the cycloaddition is reported. Cycloaddition to chiral vinylphosphine derivatives allow the postulation of a transition state geometry able to explain the diastereoface control of the allylic phosphorus stereocentre.