Highly Linear Selective Cobalt-Catalyzed Addition of Aryl Imines to Styrenes: Reversing Intrinsic Regioselectivity by Ligand Elaboration

Nickel-Catalyzed Regioselectivity-Switchable Hydroheteroarylation of Vinylarenes with Electron-Rich Heteroarenes

We report the first example of a regioselectivity switch in the hydroheteroarylation of vinylarenes with electron-rich heteroarenes, including benzofurans, benzothiophenes, and indoles, using an expedient ligand-controlled strategy. In the presence of NaOtBu, Ni(IMesMe)[P(OEt)3]Br2 yields C2-alkylated heteroarenes with high branched selectivity, whereas the use of Ni(IPr*OMe)[P(OEt)3]Br2 favors the formation of the corresponding linear products. This robust method also provides easy access to a range of C2-alkylated electron-rich heteroarenes without employing directing groups.

Tuning Ion Complexing To Rapidly Prepare Hollow Ag-Pt Nanowires with High Activity toward the Methanol Oxidization Reaction

Hollow Pt-based nanowires (NWs) have important applications in catalysis. Their preparation often involves a two-step process in which M (M=Ag, Pd, Co, Ni) NWs are prepared and subsequently subjected to galvanic reaction in solution containing a Pt precursor. It is challenging to achieve a simple one-step preparation, because the redox potential of Pt^IV /Pt or Pt^II /Pt to Pt is high, and therefore, Pt atoms always form first. This work demonstrates that an appropriate pH can decrease the redox potential of Pt^IV /Pt and allows the one-step preparation of high-quality hollow Pt-Ag NWs rapidly (10 min). Moreover, it is easy to realize large-scale preparation with this method. The NW composition can be adjusted readily to optimize their performance in the electrocatalytic methanol oxidization reaction (MOR). Compared with commercial Pt/C, NWs with appropriate Ag/Pt ratios exhibit high stability, activity, and CO tolerance ability.

Cationic Cobalt(III) Catalyzed Indole Synthesis: The Regioselective Intermolecular Cyclization of N-Nitrosoanilines and Alkynes

The unique regioselectivity and reactivity of cobalt(III) in the direct cyclization of N-nitrosoanilines with alkynes for the expedient synthesis of N-substituted indoles is demonstrated. In the presence of a cobalt(III) catalyst, high regioselectivity was observed when using unsymmetrical meta-substituted N-nitrosoanilines. Moreover, internal alkynes bearing electron-deficient groups, which are almost unreactive in the [Cp*Rh(III)]-catalyzed system, display good reactivity in this transformation.

Nickel-Catalyzed Insertion of Alkynes and Electron-Deficient Olefins into Unactivated sp(3) C-H Bonds

Insertion of unsaturated systems such as alkynes and olefins into unactivated sp(3) C-H bonds remains an unexplored problem. We herein address this issue by successfully incorporating a wide variety of functionalized alkynes and electron-deficient olefins into the unactivated sp(3) C-H bond of pivalic acid derivatives with excellent syn- and linear- selectivity. A strongly chelating 8-aminoquinoline directing group proved beneficial for these insertion reactions, while an air-stable and inexpensive Ni(II) salt has been employed as the active catalyst.