No abstract

Single atom catalysis has emerged as powerful techniques for catalysis due to its outstanding performance and atom economy. Controlling the hybridization of the atom with its environment is crucial in...

No abstract

Alkene hydrocarbofunctionalization represents one of the most important classes of chemical transformations, but related branched-selective examples with unactivated olefins are scarce. Here, we report that catalytic amounts of a dimeric Ni­(I) complex and an exogenous alkoxide base promote Markovnikov-selective hydroarylation­(alkenylation) of unactivated and activated olefins using organo bromides or triflates derived from widely available phenols and ketones. Products bearing aryl- and alkenyl-substituted tertiary and quaternary centers could be isolated in up to 95% yield and >99:1 regioisomeric ratios. Contrary to previous dual-catalytic methods that rely on metal-hydride atom transfer (MHAT) to the olefin prior to carbofunctionalization with a cocatalyst, our mechanistic evidence points toward a nonradical reaction pathway that begins with site-selective carbonickelation across the CC bond followed by hydride transfer using alkoxide as the hydride source. Utility of the single-catalyst protocol is highlighted through the synthesis of medicinally relevant scaffolds.

Fluorine-containing organic molecules, particularly those that bear (sp3)­C–F bonds, are rapidly gaining prominence in modern chemical synthesis. Although extensive studies have been devoted to the preparation of secondary and tertiary fluorides, crucial shortcomings remain: for example, lengthy substrate synthesis, contrived installation of difficult-to-remove directing/activating units, excessive waste generation and/or limited functional group compatibility. Here, we show that readily accessible α-monofluoro carboxylic acids, which are conventionally difficult substrates for cross-coupling, undergo direct decarboxylative cross-coupling with sp2- and sp3-hybridized organohalides to afford a wide assortment of fluorinated products. Reactions are typically promoted by a combination of 1 mol % of an Ir-based photocatalyst and 2–15 mol % of a bipyridine–Ni complex, delivering products in up to 86% yield under blue LED light irradiation. Concise synthesis of key therapeutic candidates underscores utility, complementarity, and distinct advantages compared with existing methods. DFT calculations are used to rationalize the distinct reactivity of α-fluoro carboxylic acid substrates (vs nonfluorinated parent acids) under decarboxylation conditions.

No abstract

A highly efficient Ir -catalyzed cascade cyclization of indoles and diazoes giving access to unique pentacyclic-fused carbazoles has been developed. This novel strategy expanded the application scope of coupling partners to take diazo compounds as a C2 source, and two new cycles, three new C-C and one new C-N bonds were formed in one-pot.

Aliphatic-1,3-dienes represent a problematic class of substrates for catalytic 1,2-dicarbofunctionalization due to inherent complications of undesired allylic rearrangement, consequently giving rise to inseparable isomeric product mixtures. Here, we show that aliphatic-1,3-dienes can participate in highly efficient and site-selective 1,2-diarylation, by merging with an aryl triflate and arylmetal reagent in the presence of a sizeable N-heterocyclic carbene (NHC)−Ni(0) catalyst. Adducts containing tertiary or quaternary centers and those derived from multifunctional bioactive molecules could be obtained.