Regio- and stereoselective (3 + 2)-cycloaddition reactions of nitrones with cyclic allenes.

An effective approach to access functionalized 2-cyclonona(deca)[]isoxazoles and 15-oxo-3,10-methanobenzo[][1]azacyclododecines has been developed by the reaction of -aryl-,-bis(methoxycarbonyl)nitrones with cyclonona(deca)-1,2-dienes in a one-pot fashion. The reaction of -aryl--(phenylcarbamoyl)nitrones with these allenes proceeds strictly regioselectively giving the mixtures of diastereomeric isoxazolidines containing a double bond at the C-position of the isoxazolidine ring. The quantum chemical calculations show that the regioselectivity of these reactions is in good agreement with the reactivity indices of the considered compounds.