An efficient method for the phosphine-catalyzed [3+2] cycloaddition reaction of azomethine imines with diphenylsulfonyl alkenes to give dinitrogen-fused bi- or tricyclic heterocyclic compounds in high yields has been described. Moreover, two phenylsulfonyl groups installed on the heterocyclic products could be conveniently removed or transformed to other functional groups, making the reaction more useful.

The PPh₃-catalyzed ring-expansion reaction of sulfamate-derived cyclic imines with acetylenedicarboxylates has been developed. The reaction works quite efficiently under very mild conditions to afford benzo[g][1,2,3]oxathiazocine-4,5-dicarboxylate 2,2-dioxide derivatives in high yields.

Phosphine-catalyzed [3+2] and [4+3] annulation reactions of C,N-cyclic azomethine imines with allenoates have been developed to give a variety of pharmaceutically attractive tetrahydroisoquinoline derivatives in moderate to excellent yields. The two distinct reaction pathways, [3+2] and [4+3] cyclization, depend on the nature of the nucleophilic phosphine and the allenoate. Generally, for α-alkylallenoates, the reactions always proceed with [3+2] cyclization as the major pathway no matter what phosphine was used; for α-ArCH₂-substituted allenoates, the reaction pathway was controlled by the phosphine catalyst used.