Dihalogentriphenylphosphoranes in Heterocyclic Synthesis; 15.1 A Simple One-Pot-Procedure for the Generation of Nitrilimines with the Aid of Dihalogentriphenyl-phosphoranes: 1,3-Dipolar Cycloadditions and 1,5-Electrocyclizations - Wamhoff, Heinrich; Zahran, Magdy (Synthesis, 1987)