Iron-catalyzed homo-coupling of simple and functionalized arylmagnesium reagents is described. The reaction is highly chemoselective (CN, COOEt and NO(2) groups are tolerated). The procedure was used to perform intramolecular couplings. This cyclization reaction is the key step of the total synthesis of the N-methylcrinasiadine.

Commercialization of CH 4 valorization processes is currently hampered by the lack of suitable catalysts, which should be active, selective, and stable. CH 4 oxychlorination is one of the promising routes to directly functionalize CH 4 , and lanthanidebased catalysts show great potential for this reaction, although relatively little is known about their functioning. In this work, a set of lanthanide oxychlorides (i.e., LnOCl with Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Ho) and Er-and Yb-based catalysts were synthesized, characterized, and tested. All lanthanide-based catalysts can directly activate CH 4 into chloromethanes, but their catalytic properties differ significantly. EuOCl shows the most promising catalytic activity and selectivity, as very high conversion levels (>30%) and chloromethane selectivity values (>50%) can be reached at moderate reaction temperatures (∼425 °C). Operando Raman spectroscopy revealed that the chlorination of the EuOCl catalyst surface is rate-limiting; hence, increasing the HCl concentration improves the catalytic performance. The CO selectivity could be suppressed from 30 to 15%, while the CH 4 conversion more than doubled from 11 to 24%, solely by increasing the HCl concentration from 10 to 60% at 450 °C. Even though more catalysts reported in this study and in the literature show a negative correlation between the S CO and HCl concentration, this effect was never as substantial as observed for EuOCl. EuOCl has promising properties to bring the oxychlorination one step closer to an economically viable CH 4 valorization process.

The direct conversion of CH 4 into fuels and chemicals produces less waste, requires smaller capital investments, and has improved energy efficiency compared to multistep processes. While the methane oxychlorination (MOC) reaction has been given little attention, it offers the potential to achieve high CH 4 conversion levels at high selectivities. In a continuing effort to design commercially interesting MOC catalysts, we have improved the catalyst design of EuOCl by the partial replacement of Eu 3+ by La 3+ . A set of catalytic solid solutions of La 3+ and Eu 3+ (i.e., La x Eu 1– x OCl, where x = 0, 0.25, 0.50, 0.75, and 1) were synthesized and tested in the MOC reaction. The La 3+ –Eu 3+ catalysts exhibit an increased CH 3 Cl selectivity (i.e., 54–66 vs 41–52%), a lower CH 2 Cl 2 selectivity (i.e., 8–24 vs 18–34%), and a comparable CO selectivity (i.e., 11–28 vs 14–28%) compared to EuOCl under the same reaction conditions and varying HCl concentrations in the feed. The La 3+ –Eu 3+ catalysts possessed a higher CH 4 conversion rate than when the individual activities of LaOCl and EuOCl are summed with a similar La 3+ /Eu 3+ ratio (i.e., the linear combination). In the solid solution, La 3+ is readily chlorinated and acts as a chlorine buffer that can transfer chlorine to the active Eu 3+ phase, thereby enhancing the activity. The improved catalyst design enhances the CH 3 Cl yield and selectivity and reduces the catalyst cost and the separation cost of the unreacted HCl. These results showcase that, by matching intrinsic material properties, catalyst design can be altered to overcome reaction bottlenecks.

Keywords: active species; ethyl oleate; Grubbs catalyst; Noels catalyst; olefin metathesisWithin the context of sustainable development, the use of fatty oils (obtained from the biomass) as raw materials appears to be an alternative to petroleum, [1] and metathesis can be used to produce key olefinic intermediates from fatty acid esters. Recent advances in olefin metathesis, based on the Chauvin mechanism, [2] have allowed numerous well-defined catalysts to be developed, [3] and today olefin metathesis can be used to construct complex molecular assemblies.[4] While the catalysts developed by Grubbs have been studied for the metathesis of oleate derivatives, [5] no data have been reported on the cheaper Noels type catalyst, [6] which is generated in situ by reacting [dimer and PCy 3 with a carbene initiator such as (trimethylsilyl)diazomethane (TMSD). Here, we have investigated in detail this catalytic system in the selfmetathesis of ethyl oleate (EO) (ratio of Ru, initiatior and PCy 3 , effect of temperature and solvents) and shown that [Cl 2 Ru=CHRA C H T U N G T R E N N U N G (PCy 3 ) 2 ], the Grubbs 1st generation catalyst (1-Ph, Grubbs I), [7] is in fact generated in situ. [6e] In fact, increasing the amount of PCy 3 to 2 equivs. per Ru improves slightly the conversion of EO to 27 % (entry 3). Second, the effect of the amount of initiator (TMSD), typically used in excess (2-7 equivs./Ru), was tested. First, using the experimental conditions reported by Noels et al. for the ROMP of cycloolefins {[RuCl 2 A C H T U N G T R E N N U N G (pcymene)A C H T U N G T R E N N U N G (PCy[6b] Decreasing the amount from 12 to 4 to 1 equiv. increased the conversion at 24 h from 10 to 32 to 34 %, respectively (entries 1 vs. 4 and 5). However, further decreasing the amount of TMSD is detrimental, and the conversions decreased from 25 % to 3 % when the amount of TMSD decreased from 0.5 to 0 equiv. (entries 5 vs. 6 and 7). Thus, the addition of a stoichiometric amount of TMSD per [RuCl 2 A C H T U N G T R E N N U N G (pcymene)A C H T U N G T R E N N U N G (PCy 3 )] is better for good conversions. Third, the reaction can be run between 25 and 60 8C without major influence on the conversion (33-34 %) after 24 h, while higher temperatures, e.g., 80 8C, destroy the catalyst (conversion of EO reaches 13 % and stops after 2 h, in agreement with a deactivation of the catalyst; entries 5 vs. 8 and 9).Finally, while the reaction cannot be run in neat EO, concentrations varying between 0.5 and 2.0 M can be used. It is also possible to replace chloroben-

Often the reactor or the reaction medium temperature is reported in the field of heterogeneous catalysis, even though it could vary significantly from the reactive catalyst temperature. The influence of the catalyst temperature on the catalytic performance and vice versa is therefore not always accurately known. We here apply EuOCl as both solid catalyst and thermometer, allowing for operando temperature determination. The interplay between reaction conditions and the catalyst temperature dynamics is studied. A maximum temperature difference between the catalyst and oven of + 16 °C was observed due to the exothermicity of the methane oxychlorination reaction. Heat dissipation by radiation appears dominating compared to convection in this set-up, explaining the observed uniform catalyst bed temperature. Application of operando catalyst thermometry could provide a deeper mechanistic understanding of catalyst performances and allow for safer process operation in chemical industries.

In the context of cross-coupling chemistry, the competition between the cross-coupling path itself and the oxidative homocoupling of the nucleophile is a classic issue. In that case, the electrophilic partner acts as a sacrificial oxidant. We investigate in this report the factors governing the crossversus homocoupling distribution using aryl nucleophiles ArMgBr and (hetero)aryl electrophiles Ar′Cl in the presence of an iron catalyst. When electron-deficient electrophiles are used, a key transient heteroleptic [Ar 2 Ar′Fe II ] − complex is formed. DFT calculations show that an asynchronous two-electron reductive elimination follows, which governs the selective evolution of the system toward either a cross-or homocoupling product. Proficiency of the cross-coupling reductive elimination strongly depends on both π-accepting and σ-donating effects of the Fe II -ligated Ar′ ring. The reactivity trends discussed in this article rely on two-electron elementary steps, which are in contrast with the usually described tendencies in iron-mediated oxidative homocouplings which involve single-electron transfers. The results are probed by paramagnetic 1 H NMR spectroscopy, experimental kinetics data, and DFT calculations.

Often the reactor or the reaction medium temperature is reported in the field of heterogeneous catalysis, even though it could vary significantly from the reactive catalyst temperature. The influence of the catalyst temperature on the catalytic performance and vice versa is therefore not always accurately known. We here apply EuOCl as both solid catalyst and thermometer, allowing for operando temperature determination. The interplay between reaction conditions and the catalyst temperature dynamics is studied. A maximum temperature difference between the catalyst and oven of +16 °C was observed due to the exothermicity of the methane oxychlorination reaction. Heat dissipation by radiation appears dominating compared to convection in this set‐up, explaining the observed uniform catalyst bed temperature. Application of operando catalyst thermometry could provide a deeper mechanistic understanding of catalyst performances and allow for safer process operation in chemical industries.

Methane oxychlorination (MOC) is a promising reaction for the production of liquefied methane derivatives. Even though catalyst design is still in its early stages, the general trend is that benchmark catalyst materials have a redox-active site, with, e.g., Cu2+, Ce4+, and Pd2+ as prominent showcase examples. However, with the identification of nonreducible LaOCl moiety as an active center for MOC, it was demonstrated that a redox-active couple is not a requirement to establish a high activity. In this work, we show that Mg2+–Al3+-based mixed-metal oxide (MMO) materials are highly active and stable MOC catalysts. The synergistic interaction between Mg2+ and Al3+ could be exploited due to the fact that a homogeneous distribution of the chemical elements was achieved. This interaction was found to be crucial for the unexpectedly high MOC activity, as reference MgO and γ-Al2O3 materials did not show any significant activity. Operando Raman spectroscopy revealed that Mg2+ acted as a chlorine buffer and subsequently as a chlorinating agent for Al3+, which was the active metal center in the methane activation step. The addition of the redox-active Eu3+ to the nonreducible Mg2+–Al3+ MMO catalyst enabled further tuning of the catalytic performance and made the EuMg3Al MMO catalyst one of the most active MOC catalyst materials reported so far. Combined operando Raman/luminescence spectroscopy revealed that the chlorination behavior of Mg2+ and Eu3+ was correlated, suggesting that Mg2+ also acted as a chlorinating agent for Eu3+. These results indicate that both redox activity and synergistic effects between Eu, Mg, and Al are required to obtain high catalytic performance. The importance of elemental synergy and redox properties is expected to be translatable to the oxychlorination of other hydrocarbons, such as light alkanes, due to large similarities in catalytic chemistry.