Copper-Mediated Coupling of Boronic Acids, Amines, and Carbon Disulfide: An Approach to Organic Dithiocarbamates

Abstract

A. General Remarks 1 H and 13 C NMR spectra were recorded using a Bruker DRX-400 spectrometer using CDCl 3 as solvent and TMS as an internal standard. The chemical shifts are referenced to signals at 7.26 and 77.0 ppm, respectively. IR spectra were obtained either as potassium bromide plates or as liquid films between two potassium bromide plates with a Bruker TENSOR 27 spectrometer. Melting points were determined with a Büchi Melting Point B-545 instrument. All substrates were commercially purchased and used without further purification. Mass spectra were recorded on a Thermo ISQ-II spectrometer at an ionization voltage of 70 eV equipped with a DB-WAX capillary column (internal diameter: 0.25 mm, length: 30 m). B. General procedure for the preparation of dithiocarbamates 3 A 25 mL dried Schlenk tube was charged with boronic acid 1 (0.5 mmol), amine 2 (2.5 mmol), CS 2 (1.0 mmol), Cu(OAc) 2 (1.0 mmol), K 2 CO 3 (1.5 mmol) and MeCN (4 mL) at room temperature. The reaction mixture was stirred at 60 °C for 10 h under air. After the reaction was completed, the mixture was cooled to room temperature and filtered through a plug of celite. The filtrate was then concentrated in vacuo to afford the crude product, which was then subjected to chromatography on silica gel with hexanes/EtOAc (20:1) to give the desired product 3.

Copper‐Catalyzed S‐Arylation Starting from Arylboronic Acids and Tetraalkylthiuram Disulfide

“…Gratifyingly, the desired product phenyl dithiocarbamate (3a) was obtained in 42 % yield when the reaction was conducted in the presence of CuI/K 2 CO 3 in DMF at 80°C under open air (Table 1, entry 1). The product yield increased significantly when the reaction temperature increased (entries [19][20][21], and 100°C was chosen as the optimal reaction temperature. No desired product was detected when other metal salts such as Pd(OAc) 2 , PdCl 2 , or FeCl 3 were employed as catalysts (entries 8-10).…”

“…No desired product was detected when other metal salts such as Pd(OAc) 2 , PdCl 2 , or FeCl 3 were employed as catalysts (entries 8-10). It is worth noting that dithiocarbamate-containing olefin compounds 3s, 3t, and 3u could be synthesized smoothly with 88, 81, and 80 % yield, respectively (entries [19][20][21]. The results revealed that Cs 2 CO 3 was the most efficient, giving the desired product in 65 % yield (entry 11).…”

“…[9] Their versatile application and biological properties has actuated the development of synthetic procedures for these compounds. [14] Other protocols such as onepot three component reactions of amines, carbon disulfide with electrophiles including alkyl halides [15] or aryl halides, [16] aryl diazonium fluoroborates, [17] pentafluorobenzonitriles, [18] or benzene boronic acid [19] were reported. [10] A couple of metal-free procedures involve the reaction of the sodium salt of dithiocarbamic acid with diazonium chloride [11] and diaryl diazonium salts in the presence of hypervalent iodine, [12] the reaction of certain organometallic reagents with tetramethyllithium disulfide, [13] coupling of sodium dithiocarbamates with aryl iodides or halobenzene.…”

“…[10] A couple of metal-free procedures involve the reaction of the sodium salt of dithiocarbamic acid with diazonium chloride [11] and diaryl diazonium salts in the presence of hypervalent iodine, [12] the reaction of certain organometallic reagents with tetramethyllithium disulfide, [13] coupling of sodium dithiocarbamates with aryl iodides or halobenzene. [14] Other protocols such as onepot three component reactions of amines, carbon disulfide with electrophiles including alkyl halides [15] or aryl halides, [16] aryl diazonium fluoroborates, [17] pentafluorobenzonitriles, [18] or benzene boronic acid [19] were reported. However, these methods suffer from high cost, environmental issues, difficulty in preparing the reagent, high reaction temperatures, or multiple reaction steps, which limit their applications.…”

Chemoselective C–S/S–S Formation between Diaryl Disulfides and Tetraalkylthiuram Disulfides

“…So far, a variety of methods are successfully employed for the synthesis of aryl dithiocarbamates, while there are very few reports for the synthesis of dialkylcarbamo(dithioperoxo)thioate . Typical approaches to aryl dithiocarbamates involve the coupling reaction of one‐pot three‐component reactions using amines and carbon disulfide with electrophiles, including alkyl or aryl halides, arenediazonium fluoroborates, N ‐(phenylthio)phthalimide and arylboronic acids . Although remarkable progress has been made, these methods are still limited by tedious operation steps, flammable and explosive substrates or reagents, and high substrate molar ratios.…”