A new approach has been developed for the synthesis of 8-substituted 2H-chromenes, featuring a novel cascade aromatic Claisen rearrangement/o-quinone methide formation/6π-electrocyclization. This new method was demonstrated with 28 examples tolerating different substitutions at alkenes, allylic and aromatic ring and with total syntheses of three 2H-chromene natural products.

The oxone–halide green oxidation system is extended to the oxidation of primary amides and aromatic aldehydes (with sodium azide) to generate N -haloamide and acyl azides, respectively, for subsequent Hofmann and Curtius rearrangements.