Reductive Hydrodehalogenation of Halogenated Carboxylic Acid Derivatives Using a DMSO/HCOONa·2H₂O System

Abstract

A practical and operationally simple hydrodehalogenation of halogenated carboxylic acid derivatives using a DMSO/ HCOONa•2H 2 O system is developed. This protocol avoids the involvement of light irradiation, electrochemical apparatus, transition metals, radical initiators, strong bases, and other additional additives. Control experiments suggest that HCOONa might function as a hydride donor in the reduction process via nucleophilic substitution or addition to achieve the hydrodehalogenation.

3-Chloropropylbis(catecholato)silicate as a Bifunctional Reagent for the One-Pot Synthesis of Tetrahydroquinolines from o-Bromosulfonamides

“…Prepared according to General Procedure B from o- bromoacetanilide 17 ( 24 ) (0.086 g, 0.40 mmol, 1.0 equiv), 3-chloropropyl bis(catacholato)silicate (0.254 g, 0.60 mmol, 1.50 equiv), 4CzIPN (0.009 g, 3 mol %), and pre-formed NiCl 2 (dtbbpy) (0.008 g, 5 mol %) in NMP (4 mL). Workup and purification by chromatography on SiO 2 afforded 18 (0.049 g, 58%) as a thick oil that solidified on standing: mp 81–84 °C; 1 H NMR (400 MHz, CDCl 3 ) δ 7.66 (d, 1 H, J = 8.0 Hz), 7.34 (br s, 1 H), 7.48 (d, 1 H, J = 7.6 Hz), 7.25–7.02 (m, 3 H), 3.50 (t, 2 H, J = 6.0 Hz), 2.71 (t, 2 H, J = 7.2 Hz), 2.14 (s, 3 H), 2.04–1.94 (m, 2 H); 13 C{ 1 H} NMR (100 MHz, CDCl 3 ) δ 169.1, 135.5, 132.5, 129.9, 127.3, 125.9, 124.8, 44.9, 32.9, 27.9, 24.3; IR (ATR) 3258 (w), 3040 (w), 1660 (s), 1529 (s), 1498 (s), 1442 (s), 1370 (w), 1265 (w), 751 (s) cm –1 ; HRMS (ESI+) calcd for C 11 H 14 NClONa [M + Na + ] 234.0662, found 234.0659.…”