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A series of ruthenium [NNN]- or [NCN]-type complexes (3–7) bearing PPh3 ancillary ligands have been synthesized from pyridine- or phenylene-bridged bis(triazoles) 1 and 2. In the case of [NNN]-pincer complex 3, an unusual and unexpected cis-orientation adopted by two sterically demanding PPh3 ligands was observed, and such configuration proved to be unchanged in solution for a long time. By contrast and as expected, the two phosphines are found to be trans to each other in the case of [NCN]-type pincer complex 4, but an oxidation of RuII center to RuIII occurred. Complex cis-3 underwent ligand exchanges leading to the formations of diphosphine derivatives 5 and 6. As a representative, cis-3 was treated with the base in isopropanol affording a mixture of Ru–hydrido complexes with various phosphine binding modes, one of which (trans-7) bearing two trans-standing phosphines has been successfully isolated and fully characterized. The catalytic performances of all newly synthesized Ru complexes have been examined and compared in transfer hydrogenations of ketones and enones, in which mono-phosphine complexes proved to be significantly superior to their diphosphine counterparts. The catalytic process proved to involve Ru–H key intermediates, but the trans-oriented Ru–H species is unlikely to be the main catalytic contributor. In particular, the best performer cis-3 exhibits high chemoselectivity in certain cases catalyzing α,β-unsaturated ketones, whose behavior is quite different compared to most precedents.

In this letter, we successfully explored a cascade Pd/Cu-catalyzed intermolecular C(sp3)–H arylation of amides and intramolecular C–N coupling reaction. This method provides a one-pot strategy to synthesize 3,4-2H-quinolinone with good regioselectivity of C–H arylation and C–N coupling from C–I and C–X bonds from readily available starting materials.

The first phthalocyanine (Pc) macrocycle-containing [FeFe]-hydrogenase model complex, (i-BuO)8PcRu(CO)(μ-PDT)[(Ph2P)2NCH2C5H4N]Fe2(CO)4 (6), has been prepared by a multistep synthetic route. The treatment of 4-picolylamine with Ph2PCl/Et3N in CH2Cl2 at room temperature gave 4-picolyl-substituted azadiphosphine (Ph2P)2NCH2C5H4N (1), whereas further treatment of 1 with diiron complex (μ-PDT)Fe2(CO)6 in refluxing o-xylene produced the 4-picolylazadiphosphine-chelated diiron complex (μ-PDT)[(Ph2P)2NCH2C5H4N]Fe2(CO)4 (2). While 3,6-dihydroxyphthalonitrile reacted with i-BuBr/K2CO3 in DMF at 80 °C to give 3,6-diisobutoxyphthalonitrile 3, further reaction of 3 with lithium wire in refluxing i-BuOH afforded isobutoxyphthalocyanine (i-BuO)8PcH2 (4). Furthermore, 4 reacted with Ru3(CO)12 in refluxing PhCN to give ruthenium phthalocyanine (i-BuO)8PcRu(CO)2 (5). Finally, CO substitution reaction of 5 with diiron complex 2 in the presence of Me3NO in CH2Cl2 resulted in formation of the targeted model complex 6. While ...

Selective cleavage of an inert C-C bond followed by C-O/N bond formation through a long-distance aryl migration from a carbon to a nitrogen center via Ag catalysis is reported. The migration products were easily converted into γ-hydroxy amines and tetrahydroquinoline derivatives in quantitative yields. Preliminary mechanistic studies indicated a radical pathway.

A rhodium(III)-catalyzed cross-coupling of benzyl thioethers and aryl carboxylic acids through the two directing groups is reported. Useful structures with diverse substituents were efficiently synthesized in one step with the cleavage of four bonds (CH, CS, OH) and the formation of two bonds (CC, CO). The formed structure is the privileged core in natural products and bioactive molecules. This work highlights the power of using two different directing groups to enhance the selectivity of a double CH activation, the first of such examples in cross-oxidative coupling.

A concise and environmentally benign protocol for lignin model fragmentation was developed by using cheap and commercially available sodium persulfate as an oxidant. The predominant lignin β-O-4 or β-1 model was fragmented into high-value aromatic aldehydes. The other lignin models, such as α-O-4, 4-O-5, and 5–5′, showed good reactivity in this system.

Two new ferrocenyl (Fc) group containing 1,5-diaza-3,7-diphosphacyclooctane ligands, PFc2NAr2 (1, Ar = Ph; 2, Ar = p-BrC6H4), were prepared by reaction of FcPH2 with 2 equiv of paraformaldehyde in glycol followed by treatment of the resulting FcP(CH2OH)2 with 1 equiv of aniline or p-bromoaniline in 79% and 67% yields, respectively; however, ligands 1 and 2 could be also prepared by treatment of the isolated and purified FcP(CH2OH)2 with 1 equiv of aniline or p-bromoaniline under similar conditions in 80% and 72% yields, respectively. Further treatment of 1 or 2 with the complex salt [Ni(MeCN)6](BF4)2 in MeCN at room temperature resulted in formation of the first ferrocenyl-containing complexes [Ni(PFc2NAr2)2](BF4)2 (3, Ar = Ph; 4, Ar = p-BrC6H4) in 95% and 90% yields, respectively. Compounds 1–4 were structurally characterized by elemental analysis and spectroscopy and particularly for 1, 2, and 4 by X-ray crystallography. When the cyclic voltammetric behavior of 1–4 was investigated, 3 and 4 were found t...

The first example of the transition-metal-catalyzed direct intermolecular C–H bond addition to ketones was achieved by using a rhodium catalyst. A significant influence of the directing group on the reactivity was observed, and sterically more hindered directing groups could promote the reaction. In addition, intermolecular hydrogen bonding played a role in stabilizing the product. The substrate scope for the quinoline derivatives was very good.

Dibenzopyranones were synthesized by a palladium-catalyzed phenol-directed C-H activation/carbonylation of 2-phenylphenol derivatives in the presence of CO. Pd(OAc)2 was used as a catalyst and Cu(OAc)2 as a catalytic oxidant in the presence of air.

The first two model compounds for [FeFe]-hydrogenases that contain a subphthalocyanine (SubPc) macrocycle, namely, [{(μ-SCH2)2N(CH2)2CO2-3-C6H4S2C6H4-3′-O(SubPc)}Fe2(CO)6] (5) and [{(μ-SCH2)2NC6H4-4-O(SubPc)}Fe2(CO)6] (8), have been synthesized and structurally characterized. The treatment of chlorosubphthalocyanine (SubPc-Cl, 1) with (3-HOC6H4S)2 in toluene gave the corresponding phenoxy-substituted SubPc derivative 3-HOC6H4S2C6H4-3′-O(SubPc) (2) in 78 % yield, whereas the reaction of in-situ-generated [(μ-HOCH2S)2Fe2(CO)6] (3) with β-alanine afforded diiron complex [{(μ-CH2S)2N(CH2)2CO2H}Fe2(CO)6] (4) in 53 % yield. Further treatment of 2 with 4 in the presence of N,N′-dicyclocarbodiimide (DCC) and N,N-dimethyl-4-aminopyridine (DMAP) in CH2Cl2 resulted in the formation of model compound 5 in 86 % yield. Model compound 8 could be prepared by two methods. One method involves the reaction of in-situ-generated 3 with 4-aminophenol in tetrahydrofuran (THF) to give diiron complex [{(μ-CH2S)2NC6H4OH-4}Fe2(CO)6] (6) in 61 % yield and further treatment of SubPc-Cl (1) with 6 in toluene to give 8 in 13 % yield. The other method involves the reaction of SubPc-Cl (1) with silver triflate (AgOTf) followed by treatment of the resulting intermediate SubPc-OTf (7) with 6 in the presence of Et3N to produce 8 in a much higher yield (59 %). All the new precursors (2, 4, and 6) and the model compounds 5 and 8 have been fully characterized by elemental analysis and various spectroscopy techniques, as well by X-ray crystallography for 2, 4, 6, and 8. In addition, the photoinduced H2 production catalyzed by model 8 was preliminarily investigated.

In this letter, we report an efficient and concise protocol for Cu-catalyzed cross-coupling of unactivated alkyl halides/peusudohalides with terminal alkynes to afford internal alkynes with the assistance of various amides as directing groups. Different alkyl halides/pseudohalides exhibited excellent reactivities, and the inactivated alkyl chlorides and sulfonates showed better reactivity than bromides/iodides. This is the first successful example to apply alkyl chlorides and sulfonates directly in cross-coupling with terminal alkynes in the absence of any additives. A Cu catalyst was found to be more effective than other transition metal catalysts. This reaction also exhibited a broad substrate scope with respect to terminal alkynes.

In this letter, we report an efficient and concise protocol for Cu-catalyzed cross-coupling of unactivated alkyl halides/peusudohalides with terminal alkynes to afford internal alkynes with the assistance of various amides as directing groups. Different alkyl halides/pseudohalides exhibited excellent reactivities, and the inactivated alkyl chlorides and sulfonates showed better reactivity than bromides/iodides. This is the first successful example to apply alkyl chlorides and sulfonates directly in cross-coupling with terminal alkynes in the absence of any additives. A Cu catalyst was found to be more effective than other transition metal catalysts. This reaction also exhibited a broad substrate scope with respect to terminal alkynes.

Selective cleavage of an inert C–C bond followed by C–O/N bond formation through a long-distance aryl migration from a carbon to a nitrogen center via Ag catalysis is reported. The migration products were easily converted into γ-hydroxy amines and tetrahydroquinoline derivatives in quantitative yields. Preliminary mechanistic studies indicated a radical pathway.

The first example of the transition-metal-catalyzed direct intermolecular C–H bond addition to ketones was achieved by using a rhodium catalyst. A significant influence of the directing group on the reactivity was observed, and sterically more hindered directing groups could promote the reaction. In addition, intermolecular hydrogen bonding played a role in stabilizing the product. The substrate scope for the quinoline derivatives was very good.

Dibenzopyranones were synthesized by a palladium-catalyzed phenol-directed C-H activation/carbonylation of 2-phenylphenol derivatives in the presence of CO. Pd(OAc)2 was used as a catalyst and Cu(OAc)2 as a catalytic oxidant in the presence of air.

The [3 + 2] cycloaddition reaction of C(60) with ethyl isonicotinoylacetate in the presence of piperidine in PhCl at room temperature or in the presence of Mn(OAc)(3) in refluxing PhCl gave the pyridyl-containing dihydrofuran-fused C(60) derivative (4-C(5)H(4)N)C(O)═C(C(60))CO(2)Et (1), whereas the phenyl-containing C(60) derivative PhC(O)═C(C(60))CO(2)Et (2) was similarly prepared by [3 + 2] cycloaddition reaction of C(60) with ethyl benzoylacetate in the presence of piperidine or Mn(OAc)(3). More interestingly, one of the new porphyrin-fullerene dyads, i.e., [4-C(5)H(4)NC(O)═C(C(60))CO(2)Et]·ZnTPPH (3, ZnTPPH = tetraphenylporphyrinozinc), could be prepared by coordination reaction of the pyridyl-containing C(60) derivative 1 with equimolar ZnTPPH in CS(2)/hexane at room temperature. In addition, the β-keto ester-substituted porphyrin derivative H(2)TPPC(O)CH(2)CO(2)Et (4) was prepared by a sequential reaction of HO(2)CCH(2)CO(2)Et with n-BuLi in 1:2 molar ratio followed by treatment with H(2)TPPC(O)Cl in the presence of Et(3)N and then hydrolysis with diluted HCl, whereas the porphyrinozinc derivative ZnTPPC(O)CH(2)CO(2)Et (5) could be prepared by coordination reaction of 4 with Zn(OAc)(2) in refluxing CHCl(3)/MeOH. Particularly interesting is that the second new porphyrin-fullerene dyad H(2)TPPC(O)═C(C(60))CO(2)Et (6) could be prepared by [3 + 2] cycloaddition reaction of 4 with C(60) in the presence of piperidine in PhCl at room temperature. In addition, treatment of 6 with Zn(OAc)(2) in refluxing CHCl(3)/MeOH afforded the third new dyad ZnTPPC(O)═C(C(60))CO(2)Et (7). All the new compounds 1-7 were characterized by elemental analysis and various spectroscopic methods and particularly for 2, 3, and 5 by X-ray crystallography. The five-component system consisting of an electron donor EDTA, dyad 3, an electron mediator methylviologen (MV(2+)), the catalyst colloidal Pt, and a proton source HOAc was proved to be effective for photoinduced H(2) evolution. A possible pathway for such a type of H(2) evolution was proposed.

A carboxylic ester group was introduced to three series of isoindolinedione substituted benzoxazinone derivatives. Some of these analogues exhibited good herbicidal activities, and the injury symptoms against weeds included leaf cupping, crinkling, bronzing, and necrosis, typical of protox inhibitor herbicides. Structurally, they were classified as Chemical Group A (4-carboxylic ester group-6-isoindolinyl-benzoxazinones), B (4-carboxylic ester group-7-isoindolinyl-benzoxazinones), and C (4-carboxylic ester group-6- tetrahydroisoindolinyl-benzoxazinones). All of the tested compounds were structurally confirmed by (1)H NMR, IR, mass spectroscopy, and elemental analysis. Preliminary bioassay data of these three classes of compounds showed that, in general, the order of the herbicidal effectiveness is C > A > B. Several of the lead compounds, for example, C10 (methyl 2-(6-(1,3-dioxo-4,5,6,7-tetrahydro-1H-isoindol-2(3H)-yl)-7-fluoro-2-methyl-3-oxo-2H-benzo[b][1,4] oxazin-4(3H)-yl) propano-ate), C12 (ethyl 2-(6-(1,3-dioxo-4,5,6,7-tetrahydro-1H-isoindol-2(3H)-yl)-7-fluoro-2- methyl-3-oxo-2H-benzo[b][1,4]oxazin-4(3H)-yl) propanoate), and C13 (ethyl 2-(6-(1,3-dioxo-4,5,6,7-tetrahydro-1H-isoindol-2(3H)-yl)-7-fluoro-2-methyl-3-oxo-2H-benzo-[b][1,4]oxazin-4(3H)-yl) butanoate), exhibited greater than 80% control at 75 g a.i./ha in both pre- and postemergence treatments against dicotyledonous weeds, such as Abutilon theophrasti Medic, Chenopodium album L., and Amaranthus ascendens L., and monocotyledon weeds, such as Digitaria sanguinalis L., Echinochloa crus-galli L., and Setaria viridis L. On the basis of advanced screening tests and crop selectivity, compounds C10, C12, and C13 are safer to crops than flumioxazin. Compounds C10, C12, and C13 are potent to develop as pre-emergent herbicides used in peanut, soybean, maize, and cotton fields.