Synthesis of Terphenyls and Quaterphenyls via the Nickel N-Heterocyclic Carbene-Catalyzed Cross-Coupling of Neopentyl Arenesulfonates with Aryl Grignard Reagents

Abstract

Various terphenyl and quaterphenyl derivatives were prepared by the Ni-NHC catalyzed cross coupling of the corresponding biphenyl-and terphenyl-sulfonates with arylmagnesium bromides. The reactions proceeded rapidly via a nucleophilic aromatic substitution of the alkoxysulfonyl moieties by the aryl nucleophiles to afford high yields within just 1.5 h at room temperature in spite of the low reactivity of the sulfur electrophiles.

Tuning the π-bridge of quadrupolar triarylborane chromophores for one- and two-photon excited fluorescence imaging of lysosomes in live cells

“…Due to the strong acceptor strength of the boron moiety, which lowers the energies of the virtual orbitals, the low-energy absorption maxima are red-shifted by up to 4334 cm –1 compared with those of the analogous compounds 1A–5A (Scheme 4). Compounds 1A–4A were previously reported,122,130–132 whereas compound 5A was synthesized as part of the present study.…”

Nickel N-Heterocyclic Carbene-Catalyzed C–C Bond Formation: Reactions and Mechanistic Aspects

“…Even steric congestion was partially tolerated, as demonstrated by good conversion of 2-substituted chloroaryls; nevertheless, two ortho -substituents hamper useful conversions . The Ni­(acac) 2 /IPr·HBF 4 (1:1–5 mol %) catalytic system was also successful for KTC coupling of aryl fluorides (13 examples) and neopentyl arenesulfonates (36 examples) at room temperature (Scheme ). Regarding the mechanism, initial observations of the crude reaction mixtures by 13 C NMR spectroscopy were consistent with a catalytically active imidazol-2-ylidene complex of nickel(0) .…”

Practical Synthesis of Novel Symmetrical and UnsymmetricalTetrakis(aryl/heteroaryl) Adducts Containing Polyconjugated Linkages

“…The typical ways for preparing terphenyl derivatives include multicomponent reactions such as Brønsted acid catalysed cyclization, [10,11] benzannulation, [8,12–14] cyclotrimerization, [15–17] and others [5,18,19] . However, aryl‐aryl coupling reactions have received considerable attention for the synthesis of terphenyl analogues via C(sp2)−C(sp2) bond formation between two substrates [8,20] . Among them, Suzuki‐Miyaura coupling (SMC) reactions catalysed by Pd‐complexes have been realized as a simple and powerful method to access various polyaryl derivatives such as biaryl, [21] terphenyl and quaterphenyls [22] .…”

“…[5,18,19] However, aryl-aryl coupling reactions have received considerable attention for the synthesis of terphenyl analogues via C(sp2)À C(sp2) bond formation between two substrates. [8,20] Among them, Suzuki-Miyaura coupling (SMC) reactions catalysed by Pd-complexes have been realized as a simple and powerful method to access various polyaryl derivatives such as biaryl, [21] terphenyl and quaterphenyls. [22] Considering the toxicity and the high cost of Pd-based catalysts, much efforts have been recently devoted to replace palladium with other TMs (TMs = transition metals such as Fe, Ni, Co, and Cu).…”