Synthesis of Fused Six-Membered Lactams to Isoxazole and Isoxazoline by Sequential Ugi Four-Component Reaction and Intramolecular Nitrile Oxide Cyclization

The advanced organic chemistry experiments describe the preparation of fused six-membered lactams to isoxazole and isoxazoline by employing Ugi four-component reaction (U-4CR) and intramolecular nitrile oxide cyclization (INOC) synthetic sequence. The experiments were carried out in 28 h (overnight for U-4CR) and 2 h (for INOC) using commercially available starting materials. The two-step reaction involves the in situ imine formation in the one-pot multicomponent reaction and in situ nitrile oxide formation in the INOC. The experiments are useful in the organic chemistry curriculum for the introduction of a onepot multicomponent reaction and 1,3-dipolar cycloaddition reactions.