Three‐Component Cycloadditions to Prepare Isooxazoline‐Fused Furo[3,2‐b]quinolines

Abstract A variety of isooxazoline‐fused furo[3,2‐b]quinolines containing four stereocenters were prepared in 40 %‐87 % yields with high regioselectivity and diastereoselectivity. The control experimental results revealed that the reaction underwent in the order of [4+2] cycloaddition and sequential [3+2] cycloaddition between aza‐ ortho ‐quinone methides (ao‐QM) generated from 2‐chloromethyl anilines, furans, and nitrile N ‐oxides generated from hydroxamoyl chlorides. The present method features mild reaction conditions, broad substrate scope, high diastereoselectivity of four stereocenters, and novel scaffolds of isooxazoline‐fused furo[3,2‐b]quinolines.