C(sp²)–C(sp²) Reductive Cross-Coupling of Triarylphosphines with Aryl Halides by Palladium/Nickel Co-catalysis

Abstract

Herein, we report the first general C(sp 2 )−C(sp 2 ) reductive cross-coupling reaction of diverse triarylphosphines with a wide range of aryl halides by palladium/nickel co-catalysis. This protocol offers a unique route for the synthesis of biaryl compounds via the activation of inert C(Ar)−P bonds. The mechanistic studies demonstrate that the formation of the phosphonium salts in situ plays a key role in the catalytic cycle.

Iodine Anion Catalyzed Cross-Dehydrogenative Aromatization for Access to Aromatic Amines

“…1 H NMR (400 MHz, CDCl 3 ) δ 7.62–7.70 (m, 2H), 7.42 (t, J = 7.5 Hz, 2H), 7.34–7.27 (m, 2H), 6.88 (d, J = 7.6 Hz, 1H), 6.75–6.74 (m, 1H), 6.57 (dd, J = 8.1, 2.3 Hz, 1H), 3.34 (t, J = 6.6 Hz, 4H), 2.03–1.99 (m, 4H) ppm. These data matched with those previously reported in the literature …”

Nickel‐Catalyzed Cross‐Electrophile Coupling of Triazine Esters with Aryl Bromides

“…Aside from the broad use of organic halides and pseudohalides in cross‐electrophile couplings, the pursuit of alternative electrophiles for such organic transformations is also highly sought after in recent years. [ 5 ] For example, a plethora of other electrophiles, such as organoammonium salt, [ 6 ] Katritzky salt, [ 7 ] aryl methyl ether, [ 8 ] aliphatic alcohol, [ 9 ] triarylphosphine, [ 10 ] heterocyclic phosphonium salt, [ 11 ] thianthrenium salt, [ 12 ] sulfone, [ 13 ] N ‐hydroxyphthalimide ester, [ 14 ] cyclic anhydrides, [ 15 ] aryl nitrile, [ 16 ] and diaryliodonium salt, [ 17 ] have also been demonstrated to be promising electrophilic coupling partners for such kind of cross‐electrophile couplings.…”

Synthesis of (Hetero)biaryls via Nickel Catalyzed Reductive Cross‐Electrophile Coupling Between (Hetero)aryl Iodides and Bromides

“…Numerous significant advances have been made by the groups of Weix, [5] Gong, [6] Reisman, [7] Doyle, [8] and Jarvo [9] amongst others. [10] For (hetero)biaryl XECs, the additional burden of differentiating between two C(sp 2 )-hybridized coupling partners whilst minimizing competitive homo-dimerization remains an enduring challenge. [11] In Gosmini's seminal work, a Ni-catalyzed electrochemical XEC using a sacrificial anode was first disclosed as an efficient system for the synthesis of 2-arylpyridines from the correspond-ing (hetero)aryl halides, [12] and Léonel has expanded the scope of Ni-catalyzed electrochemical XECs to include pyridazine and pyrimidine electrophiles.…”