Synthesis of diverse indene derivatives from 1-diazonaphthalen-2(1H)-ones via thermal cascade reactions.

A sequential Wolff rearrangement of 1-diazonaphthalen-2(1H)-ones followed by trapping of the ketene intermediate with primary and aromatic amines or alcohols and phenols in the presence of various aldehydes generates 1H-indene-3-carboxamides or 1H-indene-3-carboxylates. This constitutes an unprecedented three-component coupling reaction that allows for the synthesis of functionalized indene derivatives under catalyst-free thermal conditions.