Copper-Promoted Hiyama Cross-Coupling of Arylsilanes With Thiuram Reagents: A Facile Synthesis of Aryl Dithiocarbamates

We report herein a facile Hiyama cross-coupling reaction of arylsilanes with thiuram reagents (tetraalkylthiuram disulfides or tetraalkylthiuram monosulfide) enabled by copper fluoride. Compared to our previous work, this protocol is an alternative protocol for the generation of S-aryl dithiocarbamates. It features low toxic and readily available substrates, cost-effective promoter, easy performance, and provides good yields.


General information
All the reagents were obtained commercially and used without further purification. Silica gel was purchased from Qing Dao Hai Yang Chemical Industry Co. Analytical thin layer chromatography (TLC) was performed on precoated silica gel F254 plates. Compounds were visualized by irradiation with UV light (254 nm).
Analytical information: 1 H NMR and 13 C NMR spectra data were recorded by a BRUKER AVANCE III 400 MHz spectrometer ( 1 H 400 MHz, 13 C 100 MHz), using CDCl3 as the solvent with tetramethylsilane (TMS) as the internal standard at room temperature. 1 H NMR spectral data are given as chemical shifts in ppm: followed by multiplicity (s-singlet; d-doublet; t-triplet; q-quartet; mmultiplet), number of protons and coupling constants. 13 C NMR chemical shifts are expressed in ppm.
HRMS data were obtained using AB SCIEX Triple TOF 5600+ high resolution mass spectrometer (USA). The products listed below were determined by 1 H and 13 C NMR spectra. Infrared spectra were recorded with a Thermo Scientific Nicolet 6700 FT-IR Spectrometer. Melting points were determined using melting point X-4 (Gongyi Kerui) apparatus.
2 Table S1. Optimization of reaction conditions. a

Experimental Section (1) General procedures for the Synthesis of various arylsiloxanes
To a solution of tetramethyl orthosilicate (60 mmol) in 20 mL anhydrous THF was charged into a 100 mL round-bottom flask. The silane solution was then cooled to -30 °C , and the arylmagnesiumhalide solution was added dropwise (one drop per second). The solution was allowed to stir at -30 °C for 1 h and then at room temperature for 12 h. After the reaction finished, the mixture was then poured into 30 mL of hexane, and stirred for some time. Then the solution was washed with 3 × 25 mL of water, dried over Na2SO4, and concentrated in vacuo. Purification of the residue by short-path distillation to yield the desired arylsilanes. [1][2] .