Highly Regioselective Dehydrogenative Hydrazination of Tropones.

Direct C(sp)-H bond functionalization of the tropone skeleton constitutes an atom-economical strategy to access substituted tropones that exist in some bioactive compounds. Herein, we report a convenient method for the preparation of 2-hydrazinotropones via C(sp)-H bond functionalization. A variety of tropones participated in the dehydrogenative hydrazination reaction with hydrazine, delivering structurally diverse 2-hydrazinotropones in moderate to good yields with extremely high regioselectivity. This method is featured by operational simplicity and metal-free reaction conditions, thereby tolerating various functional groups.