Selective Deoxygenation of Sulfoxides to Sulfides with Phosphites Catalyzed by Dichlorodioxomolybdenum(VI)

Abstract

Chemoselective deoxygenation of sulfoxides to sulfides was carried out by P(OPh) 3 in mild conditions catalyzed by dichlorodioxomolybdenum(VI).

Pinacol as a New Green Reducing Agent: Molybdenum‐ Catalyzed Chemoselective Reduction of Sulfoxides and Nitroaromatics

“…[11] General Procedure for Deoxygenation of Sulfoxides 1 with Pinacol Catalyzed by MoO 2 Cl 2 (dmf) 2 A mixture of the corresponding sulfoxide 1 (2 mmol), pinacol (472 mg, 4 mmol), and MoO 2 Cl 2 (dmf) 2 (14 mg, 0.04 mmol) was stirred at 90 °C until the sulfoxide was consumed (method A), as determined by GC-MS or TLC, or irradiated in a 10 mL sealed tube in the microwave cavity at 120 °C for 5−10 min (method B). The reaction was cooled to rt and the crude mixture was treated with 0.5 M NaOH (25 mL) and extracted with Et 2 O (3 × 20 mL).…”

“…[10] In this field we have reported the first examples of the Mo-catalyzed deoxygenation of sulfoxides [11] and N-oxides, [12] as well as the reductive cyclization of nitroaromatics. [13] In those processes phosphorous(III)-based reagents were used as oxygen-acceptors.…”

“…Based on our previous method for the deoxygenation of sulfoxides with phosphites, [11] an initial experiment was carried out with bis(ptolyl)sulfoxide 1a as model substrate in MeCN at reflux using MoO 2 Cl 2 (dmf) 2 as catalyst and 2 equiv of pinacol as oxygen-acceptor (Table 1, entry 1). Gratifyingly, complete conversion was observed after 4 h and the corresponding sulfide 2a was isolated in 85% yield.…”

Molybdenum‐Catalyzed Deoxygenation of Heteroaromatic N‐Oxides and Hydroxides using Pinacol as Reducing Agent

“…In this field we had previously reported that dioxomolybdenum(VI) complexes, [6] which are nontoxic and inexpensive compounds, [7] are useful catalysts for the chemoselective reduction of sulfoxides [8] and N-oxides,…”

Molybdenum(VI) Dichloride Dioxide

“…The same system was explored for the reduction of nitroaromatic compounds to anilines. 5,7 (C) Aromatic and aliphatic esters were reduced to alcohols using silanes and catalytic MoO 2 Cl 2 . Imines were efficiently reduced to amines using the same system.…”