General procedure for the synthesis of 2,2'-naphthalenyl ketones from di(naphthalen-2-yl)methanol: According to the modified method of Azuma et al. (Tetrahedron, 2013, 69(6), 1694-1699), MnO2 (8.4 g, 96.7 mmol, 10 eq.) was added to stirred solution of di(naphthalen-2-yl)methanol (2.75 g 9.68 mmol, 1.0 equiv) in a solution of dichloromethane (DCM, 20 mL). The reaction was carried out at room temperature with continuous stirring for 24 hours. Upon completion of the reaction, the mixture was filtered through Celite and the filtrate was concentrated under reduced pressure to afford the target product 2,2'-naphthyl ketone (2.70 g, 9.56 mmol, 99% yield) as a colorless solid. The product could be used in the subsequent reaction without further purification. 2H); 13C NMR (100 MHz, CDCl3) δC/ppm 196.8 (1C), 135.3 (2C), 135.2 (2C), 132.3 (2C), 131.8 (2C), 127.8 (4C), 126.8 (4C), 125.9 (4C); MS (ESI) [M + Na]+: 305.1 (100); IR (vmax/cm-1): 2915, 1653, 1379, 1334, 1194, 763.
