PEG-mediated recyclable borylative coupling of vinyl boronates with olefins

Application of Green Solvents: PEG and scCO2 in the Mono- or Biphasic Catalytic Systems for the Repetitive Batch Coupling of Vinylsilanes with Vinyl Boronates toward 1-Boryl-1-silylethenes

“…Surprisingly, the silylative coupling of vinylsilanes with alkoxy and siloxy substituens (2c−e) with 1a and 1b in MPEG2000 occurred, while in toluene no borylsilylethenes were observed in the reaction mixtures. In these cases, only the homocoupling of vinyl boronates (5a or 5b) occurred (Table 2, entries 9,11,13,15,17,19). It is assumed that poly(ethers) accelerate the silylative coupling reaction or slow down the vinyl boronate homocoupling.…”

“…These systems allowed the catalyst to be reused several times without any significant changes in its activity and stability. 6,13 Moreover, no significant Ru leaching was observed. Ammonium, pyridinium, or imidazolium ILs with various anions were also used for Ru−H catalyst immobilization in the homocoupling of vinylsilanes.…”

“…These describe Ru–H catalyst immobilization and recycling in a various green solvents [e.g., PEGs, ionic liquids (ILs), and supercritical CO 2 (scCO 2 )]. These systems allowed the catalyst to be reused several times without any significant changes in its activity and stability. , Moreover, no significant Ru leaching was observed. Ammonium, pyridinium, or imidazolium ILs with various anions were also used for Ru–H catalyst immobilization in the homocoupling of vinylsilanes.…”

Organocatalytic hydroboration of carbonyl compounds promoted by choline-based ionic liquids

“…High efficiency and chemoselectivity towards the carboxyl group in the presence of the ester group was observed for substrate 8n. In the next stage of our study, bearing in mind green chemistry principles and our previous research on catalyst recycling in the synthesis of organoboron compounds, [31][32][33][60][61][62] we tested the possibility of recycling the catalyst, carrying out our reaction in a repetitive batch mode. Hydroboration of acetophenone (1a) was performed under standard conditions (1 h, rt, 2 mol% of IL1, neat).…”

Hydroelementation of diynes

“…Compound 28 has previously been described as an active catalyst in hydroboration of terminal-or internal monoalkynes in conventional and novel, green reaction media (supercritical CO 2 (scCO 2 ), ionic liquids (ILs), polyethylene glycol, (PEG)). 72,75,76,128,129 The reaction proceeded effectively for various diynes possessing electron-withdrawing or electron-donating substituents on the aryl ring, as well as for heterocyclic 1,4-di(thiophen-3-yl)buta-1,3-diyne 27c. Alkyl-substituted diynes yielded boryl-substituted enynes by cis-addition of borane to the CRC bond, but the postreaction mixture also consisted of other monoborylated enynes, bisborylfunctionalised dienes, and some undefined products.…”