An efficient Cu(I)-catalyzed Suzuki-Miyaura reaction was developed for the coupling of aryl- and heteroarylboronate esters with aryl and heteroaryl iodides at low catalyst loadings (2 mol %). The reaction proceeds under ligand-free conditions for aryl-heteroaryl and heteroaryl-heteroaryl couplings. We also conducted the first detailed mechanistic studies by synthesizing [(PN-2)CuI]2, [(PN-2)CuF]2, and (PN-2)CuPh (PN-2 = o-(di-tert-butylphosphino)-N,N-dimethylaniline) and demonstrated that [(PN-2)CuF]2 is the species that undergoes transmetalation with arylboronate esters.

We disclose a strategy for Ni-catalyzed dicarbofunctionalization of olefins in styrenes by intercepting Heck C(sp)-NiX intermediates with arylzinc reagents. This approach utilizes a readily removable imine as a coordinating group that plays a dual role of intercepting oxidative addition species derived from aryl halides and triflates to promote Heck carbometalation and stabilizing the Heck C(sp)-NiX intermediates as transient metallacycles to suppress β-hydride elimination and facilitate transmetalation/reductive elimination steps. This method affords diversely substituted 1,1,2-triarylethyl products that occur as structural motifs in various natural products.

Copper is emerging as a viable catalytic metal for cross-coupling reactions to construct carbon-carbon (C-C) bonds. Recent revelations that Cu-catalysts can execute with high efficacy the cross-couplings of a variety of organometallic reagents, including organomagnesium, organoboron, organosilicon, organoindium and organomanganese, with alkyl, aryl and heteroaryl halides clearly demonstrate the versatility of Cu-based catalytic systems in conducting these reactions. In addition, Cu-catalysts are exhibiting a unique reactivity pattern that allows ligandless cross-coupling for aryl-heteroaryl and heteroaryl-heteroaryl bond formation, a transformation that generally requires special custom-designed ligands with Pd-catalysts. This review summarises early discoveries and subsequent advancements made in the area of Cu-catalysed cross-couplings of organometallic reagents with organohalides to form C-C bonds.

We disclose a [(PhO)P]/NiBr-catalyzed regioselective β,δ-diarylation of unactivated olefins in ketimines with aryl halides and arylzinc reagents. This diarylation proceeds at remote locations to the carbonyl group to afford, after simple H workup, diversely substituted β,δ-diarylketones that are otherwise difficult to access readily with existing methods. Deuterium-labeling and crossover experiments indicate that diarylation proceeds by ligand-enabled contraction of transient nickellacycles.