Dual electronic effects achieving a high-performance Ni(II) pincer catalyst for CO photoreduction in a noble-metal-free system.

A carbazolide-(NHC) Ni catalyst (1; NHC, -heterocyclic carbene) for selective CO photoreduction was designed herein by a one-stone-two-birds strategy. The extended π-conjugation and the strong σ/π electron-donation characteristics (two birds) of the carbazolide fragment (one stone) lead to significantly enhanced activity for photoreduction of CO to CO. The turnover number (TON) and turnover frequency (TOF) of 1 were ninefold and eightfold higher than those of the reported pyridinol-(NHC) Ni complex at the same catalyst concentration using an identical Ir photosensitizer, respectively, with a selectivity of ∼100%.

Formation of Stable Ni N-Confused Porphyrins Aided by a 3-Ethoxy Group.

We report the synthesis, characterization, and reactivities of two stable Ni N-confused porphyrin (NCP) complexes. Metalation of 3-OEt NCP 1 with NiCl  ⋅ 6H O in CHCl /EtOH gave 3-OEt Ni NCP 3 initially, which was easily oxidized in air to form the Ni complex of NCP inner C-oxide 4. Bis-ethoxy-modified Ni complex 5 was synthesized by oxidation of 3 with PIFA in ethanol and CHCl .

Tungsten-Catalyzed Direct N-Alkylation of Anilines with Alcohols.

The implementation of non-noble metals mediated chemistry is a major goal in homogeneous catalysis. Borrowing hydrogen/hydrogen autotransfer (BH/HA) reaction, as a straightforward and sustainable synthetic method, has attracted considerable attention in the development of non-noble metal catalysts. Herein, we report a tungsten-catalyzed N-alkylation reaction of anilines with primary alcohols via BH/HA.

Sustainable and Selective Alkylation of Deactivated Secondary Alcohols to Ketones by Non-bifunctional Pincer N-heterocyclic Carbene Manganese.

A sustainable and green route to access diverse functionalized ketones via dehydrogenative-dehydrative cross-coupling of primary and secondary alcohols is demonstrated. This borrowing hydrogen approach employing a pincer N-heterocyclic carbene Mn complex displays high activity and selectivity. A variety of primary and secondary alcohols are well tolerant and result in satisfactory isolated yields.

Nonbifunctional Outer-Sphere Strategy Achieved Highly Active α-Alkylation of Ketones with Alcohols by -Heterocyclic Carbene Manganese (NHC-Mn).

The unusual nonbifunctional outer-sphere strategy was successfully utilized in developing an easily accessible -heterocyclic carbene manganese (NHC-Mn) system for highly active α-alkylation of ketones with alcohols. This system was efficient for a wide range of ketones and alcohols under mild reaction conditions, and also for the green synthesis of quinoline derivatives. The direct outer-sphere mechanism and the high activity of the present system demonstrate the potential of nonbifunctional outer-sphere strategy in catalyst design for acceptorless dehydrogenative transformations.

Stereoselective synthesis of sulfur-containing β-enaminonitrile derivatives through electrochemical Csp-H bond oxidative functionalization of acetonitrile.

Incorporation of nitrile groups into fine chemicals is of particular interest through C(sp)-H bonds activation of alkyl nitriles in the synthetic chemistry due to the highly efficient atom economy. However, the direct α-functionalization of alkyl nitriles is usually limited to its enolate chemistry. Here we report an electro-oxidative C(sp)-H bond functionalization of acetonitrile with aromatic/aliphatic mercaptans for the synthesis of sulfur-containing β-enaminonitrile derivatives.

Rh(iii)-catalyzed regioselective intermolecular -methylene Csp-H bond carbenoid insertion.

A Rh(iii)-catalyzed regioselective intermolecular carbenoid insertion into the -methylene Csp-H bond of acyclic aliphatic amides has been achieved, taking advantage of bidentate-chelation assistance. This methodology has been successfully applied to a broad range of linear and branched-chain -alkylamides, thus providing a practical method for the assembly of diverse beta-amino esters. Mechanism studies and density functional theory (DFT) calculations revealed that a singlet Fischer type carbene insertion an outer-sphere pathway was involved in this -methylene Csp-H bond carbenoid insertion.