Base-Free and Catalyst-Free Synthesis of Functionalized Dihydrobenzoxazoles via Vinylogous Carbonate to Carbamate Rearrangement

An unexpected, catalyst-free, and
base-free intramolecular cyclization
of N-aryloxyacrylate aldimines, under thermal conditions
leading to the synthesis of functionalized dihydrobenzoxazoles, is
reported. The reaction features a unique rearrangement of vinylogous
carbonates to vinylogous carbamates resulting in a new carbon–oxygen
and carbon–nitrogen bond construction. The reaction tolerates
a broad range of functional groups and the desired products are formed
in moderate to good yields.