The catalytic effects of in situ prepared N-heterocyclic carbenes from benzimidazole salts in Suzuki–Miyaura cross-coupling reaction and uses in catalytic preparation of 1,3,5-triphenyl-1,3,5-triazinane-2,4,6-trione from phenyl isocyanate

Abstract

Many benzimidazole salts bearing a 3-phenylpropyl substituent (1a-1h) were synthesized and their structures were identified by 1 H NMR, 13 C NMR, and IR spectroscopic methods and elemental analysis. These N-heterocyclic carbene (NHC) precursors were used as a part of a catalytic system including Pd(OAc) 2 and the base in the Suzuki-Miyaura cross-coupling reaction under microwave irradiation. They were also used as catalysts in the cyclotrimerization of phenyl isocyanate to yield 1,3,5-triphenyl-1,3,5-triazinane-2,4,6-trione. It has been observed that benzimidazole salts made a positive contribution to both catalytic reactions as a NHC precursor.

Synthesis of New Bisbenzimidazole Salts and Determination Their Ligand Activities in C-C Coupling Reactions

“…IR spectra of ligands showed a stretching band of the C=N bonds at 1561, 1561 and 1562 cm -1 . These results are coherent with the literature [27,28]. The effects of ligands derived from the new benzimidazolium halides were investigated on the Suzuki-Miyaura and Mizoroki-Heck C-C coupling reactions.…”

Furandiacylazide: A Biomass-Derived Versatile Polymer Platform toward Photodegradable and Nonflammable Polyurethanes

“…To confirm our hypothesis of isocyanurate formation, we used CsF as a catalyst because it is well known to promote the trimerization of isocyanate (Table , entry 9). − Indeed, a mostly insoluble product was obtained and the proportion of isocyanurate was substantially increased ( x : y = 2:8), as analyzed by 1 H NMR, from its sparingly soluble solution (Figure S4). We therefore speculated that if we conducted the reaction with only FDAz (i.e., without the diol), a fully isocyanurate-based network polymer would be obtained.…”

Evaluation, synthesis and structural properties of stable bisbenzimidazolium tetrafluoroborates derived from unstable benzotetraazafulvalenes

“…In our previous work, in situ C-C coupling reactions were also carried out with high activities with NHC precursors/Pd(OAc)2 catalytic systems. 14,45 Here, its catalytic contribution to C-C bond formation was evaluated when compound 1 was used in the presence of palladium acetate as the ligand (Table 2). To observe the changing in the reaction yield were used different bases like K2CO3, KOH, and NaOH.…”