4.2.6. 2-[Carboxy(4-chlorophenyl)methyl]-5-chlorobenzoic Acid (**10f**)

Prepared according to the general procedure GP1 from 6-chloro-3-(4-chlorophenyl)- 2,3-dihydro-1*H*-inden-1-one [22]. Yield 530 mg, 17%. Colorless amorphous solid. 1H NMR (400 MHz, DMSO-*d*6) *δ* 13.38 (s, 1H), 12.87 (s, 1H), 7.91–7.78 (m, 1H), 7.65–7.53 (m, 1H), 7.46–7.36 (m, 2H), 7.30–7.22 (m, 2H), 7.12–7.04 (m, 1H), 5.91 (s, 1H). 13C NMR (101 MHz, DMSO-*d*6) *δ* 173.3, 167.7, 139.1, 138.0, 133.0, 132.3, 132.3, 132.1, 132.0, 131.4, 130.3, 129.1, 52.6. HRMS (ESI/Q-TOF) *m*/*z*: [M + Na+] <sup>+</sup> Calcd for C15H10Cl2O4Na<sup>+</sup> 346.9848; Found 346.9841.
