Synthesis of (±)-3,3′-bis(4-hydroxy-2H-benzopyran): a literature correction

The synthesis of bisbenzopyran-4-ol (1) was performed through the key steps of iodination, nickel(0)-modified Ullmann-type reaction, hydrogen-transfer hydrogenation and diastereoselective reduction. The X-ray diffraction experiment of compound 9 confirmed that the reported structure in the literature was not the real natural product.