endo-Selective (3+2) cycloaddition polymerizations of nitrone monomers with olefins utilising high pressure conditions

A high pressure mediated (3+2) cycloaddition polymerization strategy has been employed to afford linear poly(isoxazolidine) architectures. Under these high pressure conditions this cycloaddition process was found to afford primarily endo-heterocycles which when translated to the polymerization should ultimately affect the tacticity and resultant properties of the polymer. The stereoselectivity occurred as a result of a lower volume of activation for the endo-transition state and the application of a ‘type-I’ regime (HOMO_Dipole-LUMO_{Dipolarophile}) cycloaddition process that features secondary orbital interactions within the extended molecular orbitals. A variety of linker segments were employed in an attempt to affect the physical properties of the polymeric cycloadducts such as T_g and solubility in order to tailor these materials for use in coating applications.