TCCA/NCS-Promoted Cascade Cyclization of β, γ-Unsaturated Compounds: Synthesis of Isoxazolines and Pyrazolines

2-Isoxazolines and 2-pyrazolines have been derived from oxime and hydrazone derivatives reacted with N-chlorosuccinimide (NCS) and trichloroisocyanuric acid (TCCA). Cyclization strategy is developed for the reaction of β, γ-unsaturated hydrazones with the TCCA to drive 2-pyrazolines and the reaction of β, γ-unsaturated oximes with NCS to derive 2-isoxalzolines. Structures of all new 2-isoxazolines and 2-pyrazolines have been elucidated by microanalyses, 1H, 13C NMR and Mass spectroscopies.