Nickel(II)-Catalyzed Unexpected [3 + 2] Cycloaddition/[3,3]-Rearrangement of <i>N</i>-Vinyl α,β-Unsaturated Nitrones with 2-Alkynyl Quinazolinones

A nickel(II)-catalyzed unexpected [3 + 2] cycloaddition/[3,3]-rearrangement cascade reaction was developed for the preparation of various polysubstituted 1-pyrroline-tethered quinazolinones containing three contiguous stereocenters in moderate to good yields with high diastereoselectivity from <i>N</i>-vinyl cinnamaldehyde nitrones and 2-alkynyl quinazolinones. Polysubstituted pyrrolizine-tethered quinazolinones were obtained in good yields when <i>N</i>-vinyl cinnamaldehyde nitrones were replaced by <i>N</i>-vinyl chalcone nitrones. The present method features a broad substrate scope, high [3,3]-rearrangement selectivity and diastereoselectivity, and two substituent bifurcated types of <i>N</i>-heterocycles.