Palladium complexes of N-heterocyclic carbenes displaying an unsymmetricalN-alkylfluorenyl/N′-aryl substitution pattern and their behaviour in Suzuki–Miyaura cross coupling

Abstract

Pd–PEPPSI complexes with a mixed N-alkylfluorenyl/N′-aryl substitution pattern were found to be considerably more active in Suzuki–Miyaura cross coupling than the standard complexes [PdCl2(IMes)(Py)] and [PdCl2(IPr)(Py)].

Plausible PEPPSI catalysts for direct C–H functionalization of five-membered heterocyclic bioactive motifs: synthesis, spectral, X-ray crystallographic characterizations and catalytic activity

“…2 ) shows the only interactions exceeding dispersion to be Br⋯Br halogen bonds (Br(02)⋯Br(03) 3.6607(8) Å). These lead to the formation of extended columns of the complex units running parallel to [001] and indicate that one way in which the complex might interact with biomolecules could be through acceptance of a nucleophilic donor on coordinated bromide, though the lability of Pd( ii )–Br bonds in aqueous media 93 renders more probable interactions occurring through nucleophilic substitution on the metal ion.…”

Stereochemical Control of Tricoordinate Copper(I) Complexes Based on N-(9-Alkyl-9-fluorenyl)-Substituted Heterocyclic Carbenes

“…(Naphthalen-1-yl)imidazole (2d), 29 N-phenylimidazole (2e), 30 the imidazolium tetrafluoroborates 5a-c, 31 and the complex [CuCl(IPr)] (6f) 32 were synthesised according to published procedures.…”

Pd–PEPPSI type complexes bearing unsymmetrical NHC ligand with phenyl‐substituted backbone: Highly efficient catalysts for Heck–Mizoroki and Suzuki–Miyaura cross‐coupling reactions

“…Some of the unsymmetrical NHC-Pd-PEPPSI complexes used as catalysts in some coupling reactions are depicted in Figure 1. [14,20,30,[34][35][36][37][38][39][40][41][42][43][44] The one that is most similar to our catalyst (without a phenyl in its backbone) was used in Heck reaction in H 2 O in the presence of tetrabutylammonium bromide (TBAB) at 100 C. Borah et al could not get any conversion with hetaryl bromides in their study. [36] Herein, we report on the synthesis and characterization of a series of NHC-Pd-PEPPSI complexes, bearing unsymmetrical NHC ligand incorporating one phenyl group in its backbone and their catalytic applications in Heck-Mizoroki and Suzuki-Miyaura cross-coupling reactions in mild conditions with no need to use any additive.…”

“…Some of the unsymmetrical NHC–Pd–PEPPSI complexes used as catalysts in some coupling reactions are depicted in Figure 1. [ 14,20,30,34–44 ] The one that is most similar to our catalyst (without a phenyl in its backbone) was used in Heck reaction in H 2 O in the presence of tetrabutylammonium bromide (TBAB) at 100°C. Borah et al could not get any conversion with hetaryl bromides in their study.…”