Iron-Catalyzed Asymmetric Tandem Spiro-Cyclization Using Dioxygen in Air as the Hydrogen Acceptor.

An efficient approach for the enantioselective formation of spirocyclic dihydrobenzofurans (III) from 1-methyl- 2-naphthols(I) and phenol derivatives (II) via a new Fe-salan complex catalyzed [aerobic oxidative ortho- quinone methideformation followed by Michael addition and asymmetric dearomatization] is developed.