Organic‐Inorganic Dual Catalytic System for the Regioselective Construction of Diverse Quinone Derivatives via Benzannulation

Efficient and regioselective synthesis of highly functionalized naphthoquinone and anthraquinone derivatives was accomplished in good yields using an organic‐inorganic dual catalyst through [4+2] cycloaddition reaction between various 1,4‐benzenediols or 1,4‐naphthalenediols and α , β ‐unsaturated aldehydes. These atom‐economic reactions rapidly provided useful cycloaddition adducts in a one‐pot reaction. The technique was successfully applied to synthesize tectoquinone, a natural compound found in red heartwood‐type Cryptomeria japonica , and 2‐(4‐methylpent‐3‐enyl)anthracene‐9,10‐dione, found in the roots of Sesamum indicum , and their analogs.