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A single-step phenylation at the non-acidic C(sp3)–H bond attached to the heteroatom of ethers and N -Boc-amines has been achieved using photoexcited 4-benzoylpyridine as a hydrogen atom transfer (HAT) catalyst. The design of electron-deficient (trifluoromethylsulfonyl)benzene derivatives, as a phenyl precursor, was critical to realizing the present transformation. Moreover, the DFT calculations indicated that the present transformation proceeds via a concerted homolytic aromatic substitution rather than via a stepwise one involving the formation of a cyclohexadienyl radical intermediate. [ABSTRACT FROM AUTHOR]

A light‐driven radical oxy‐functionalization of non‐acidic aliphatic and benzylic C(sp3)−H bonds was achieved with 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) in a single‐step by employing an aryl ketone as a sole catalyst. The transformation was initiated by homolysis of a C(sp3)−H bond in the starting substance by the photo‐excited aryl ketone. The derived carbon radical was then promptly trapped by TEMPO leading to the formation of the TEMPO‐adduct. The derived TEMPO‐adduct is synthetically versatile as an alcohol equivalent since it can be readily converted to the corresponding ketone by oxidation and to the corresponding alcohol by reduction. The key to realizing the present catalytic reaction relies on the distinctive triple role of TEMPO, which acts as the precursor of the oxygen functionality, the oxidant to regenerate the aryl ketone, and the protective group for the derived TEMPO‐adduct from over‐oxidation. [ABSTRACT FROM AUTHOR]

Helicobacter pylori extracts cholesterol from the host and converts it to its glycosides. We found that cholesteryl 6′‐O‐acyl α‐glucoside (ChAcαG) produced by H. pylori is recognised by both invariant Vα14+ NKT (iNKT) cells and a C‐type lectin receptor Mincle (Clec4e). However, it is unclear how these duplicated recognitions cooperate and contribute to host defence against H. pylori. Among T cell populations in the liver, iNKT cells predominantly expressed the T cell activation marker CD69 just after stimulation with ChAcαG. The production of IFN‐γ and IL‐4 was strictly dependent on both CD1d and Jα18 expressions, indicating the necessity of iNKT cell activation for the initiation of immune responses. Production of IFN‐γ by iNKT cells was markedly reduced by the Mincle deficiency on antigen‐presenting cells (APCs), while IL‐4 production was not significantly influenced. IL‐2 production by iNKT cell hybridomas was also diminished by the Mincle deficiency upon stimulation with APCs previously loaded with ChAcαG. Here, the immune responses of iNKT cell hybridomas stimulated with wild‐type APCs were reduced by the addition of anti‐IL‐12 blocking antibody to the level stimulated with Mincle‐deficient APCs. Collectively, these results suggest that iNKT cells can be activated with the cholesteryl glycosides via a Mincle‐dependent, IL‐12 signal‐dependent pathway and a Mincle‐independent, invariant TCR signal‐dominant pathway. iNKT cells activated via the Mincle‐dependent pathway produce IFN‐γ‐dominant cytokines; hence, they may contribute to enhancing proinflammatory responses against H. pylori infection. [ABSTRACT FROM AUTHOR]

A light-driven naphthylation was achieved at C(sp3)–H bonds attached to either oxygen or nitrogen substituents using sulfonylnaphthalenes as a naphthalene precursor in the presence of 4-benzoylpyridine at ambient temperature. The present transformation is proposed to proceed through the generation of a carbon radical species via chemoselective cleavage of the heteroatom-substituted C(sp3)–H bond by photoexcited 4-benzoylpyridine, the addition of the derived carbon radical to the electron-deficient sulfonylnaphthalene, and then rearomatization by releasing sulfinyl radical. [ABSTRACT FROM AUTHOR]

Facile C-C bond cleaving fragmentation reactions induced by the addition of nucleophiles to cyclic vinylogous acyl triflates is developed to produce acyclic acetylenic compounds. The respective reactions produce ketones, 1,3-diketones and their analogues, alcohols, and amides.

Research has been conducted on cyano compounds, thrimethylsilyl azide and allyl methyl carbonate. The study of the palladium-catalyzed three-component coupling reactions of these compounds is presented.

The addition of stabilized carbanionic nucleophiles to cyclic vinylogous acyl triflates (VATs) has triggered a ring-opening fragmentation to produce acyclic [beta]-keto ester and related products, much like those seen in the Claisen condensation. The details of the original reaction method are disclosed, including how subtle differences between the various nucleophiles have impacted the proper choice of reaction conditions for making 1,3-diketones, [beta]-keto esters and [beta]-keto phosphonates.

The production of 1,4-disubstituted imidazoles in very high yields by copper-catalyzed cross-cycloaddition between arylisocyanides and isocyanides is reported. It was noticed that during the study on copper-catalyzed pyrrole synthesis between activated alkynes and isocyanides, use of unactivated alkynes did not produce desired pyrroles, but the reaction gave imidazole 4 (EWG =[CO.sub.2]Et) in 49% yield as homo-cycloaddition product of ethyl isocyanoacetate.

Two facile deallylation protocols are developed for the preparation of N-unsubstituted triazoles and tetrazoles. The isomerization from N-allylazoles to N-vinylazoles is catalyzed by a ruthenium complex, HRuCl(CO)[PPh(sub 3)](sub 3), and the following ozonoloysis of the derived N-vinyl intermediates affords N-unsubstituted azoles.

The copper-catalyzed reaction of isocyanides (CNH2EWG) with electron-deficient alkynes (RC(triple bond)CEWG) produced 2,4-di-EWG-subsituted pyrroles selectively, whereas the phosphine-catalyzed reaction of isocyanides with activated alkynes yielded 2,3-di-EWG-substituted pyrroles. It shows that the regioselective synthesis of substituted pyrroles is achieved by merely choosing the catalyst.

A facile C-C bond cleavage reaction induced by the nucleophilic addition of Grignard or lithium reagents to vinylogous carboxylic acid triflates is described. The reaction proceeds under mild conditions, and the enol triflate substrates are easily prepared in one step from the corresponding diketones.

Research has been conducted on 3-allyl-N-(alkoxycarbonyl)indoles. The authors describe the synthesis of these compounds carried out via the reaction of 2-(alkynyl)phenylisocyanates and allyl carbonates in the presence of Pd(PPh (sub)3) (sub)4 and CuCl bimetalic catalyst.

The study explains the synthesis of allyl cyanamides and N-cyanoindoles through the palladium-catalyzed three-component coupling reaction of aryl isocyanides. Cyanamides are used as building blocks for heterocyclic compounds and also as a ligand for various metals in material science.