Nickel-Catalyzed, para-Selective, Radical-Based Alkylation of Aromatic Ketones

Abstract

A direct, para-selective, radical-based alkylation of aromatic ketones with alkanes has been developed using a nickel catalyst with oxamide as the ligand. Acetophenones bearing electron-withdrawing substituents were functionalized directly with simple alkanes with high para-selectivity while acetophenones with electron-donating groups were mainly para-functionalized. A mechanistic study indicated that C–H bond activation of the aromatic ring may be the rate-determining step of the reaction.

Ligand Promoted Olefination of Anilides for Indirectly Introducing Fluorinated Functional Groups via Palladium Catalyst

“…General Procedure for the Synthesis of L2. 23 Diamantadine hydrochloride (21 mmol, 4.53 g, 2.1 equiv) and triethylamine (50 mmol, 6.9 mL, 5.0 equiv) were added to dichloromethane (50 mL) solution, and the reaction was stirred in an ice bath for 10 min. A mixture of oxaloyl chloride (10 mmol, 0.85 mL, 1.0 equiv) and dichloromethane (20 mL) was then added to the solution slowly under cooling with an ice−water bath, and the resulting mixture was stirred at room temperature overnight.…”

Recent Advances in Transition-Metal-Catalyzed Selective C–H Alkoxycarbonyldifluoromethylation Reactions of Aromatic Substrates

“…A cyclometalated ruthenium complex not only provided ortho-selective C−Hfunctionalized products with an electrophilic reagent but also acted as a strong bulk-electronic-transient-metal functional group to realize meta-or para-selective C−H transformations. 40 The other transition metals such as palladium, [21][22][23] molybedenum, 41 and nickel 42 all can used as an effective weak lewis acid to coordinate with the functional group adjacent to aromatic ring, leading to the para-selective C-H functionalizations. Although the reason is unclear, we may propose that when the metal complex coordinate with the main functional group on aromatic compounds, the introduction of the metal complex promotes the activation of the aromatic ring, and the steric hindrance of the ligand on the metal complex changes the dimensional environment of, meta, and para positions, leading to the reaction selective happens at the less hindered position on the aromatic ring.…”

Regioselective Friedel–Crafts Acylation Reaction Using Single Crystalline and Ultrathin Nanosheet Assembly of Scrutinyite-SnO2

“…Again, the Friedel–Crafts (FC) acylation of aromatic substrates with acid halides is a fundamental and important conversion in organic synthesis. − In particular, regioselective FC acylation to synthesize aromatic ketones have potential significance in chemical industry as the ketones are involved in the preparation of various synthetic intermediates, chemical feedstocks, pharmaceuticals, and fine chemicals . Although the aromatic ketones have tremendous applications, yet conventional strategies to produce such ketones often suffer from major challenges of complicated synthetic procedures and environmental concerns. , The use of homogeneous catalysts, for example, protic acids, soluble metal halides, and substituted anhydrides in stoichiometric amounts and other homogeneous catalysts, for example, Ln­(OTf) 3 -LiClO 4 , LiClO 4 -acyl anhydride complex, (PhCN) 2 PtCl 2 /AgSbF 6 , Re-Br­(CO) 5 , and so on in the catalytic amount spectacle certain progress in the reaction.…”