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Numerous hydride‐abstracting agents generate the same cationic intermediate, but substrate features such as intermediate cation stability, oxidation potential, and steric environment can influence reaction rates in an oxidant‐dependent manner. This manuscript provides experimental data to illustrate the role that structural features play in the kinetics of hydride abstraction reactions with commonly used quinone‐, oxoammonium ion‐, and carbocation‐ based oxidants. Computational studies of the transition state structures and energies explain these results and energy decomposition analysis calculations reveal unique sensitivities to electrostatic attraction and steric repulsions. Rigorous rate studies of select reactions validated the capacity of the calculations to predict reactivity trends. Additionally, kinetics studies demonstrate the potential for product inhibition in DDQ‐mediated reactions. These studies provide a clear guide to select the optimal oxidant for structurally disparate substrates and lead to predictions of reactivity that were validated experimentally.

Ketone functionalization is a cornerstone of organic synthesis. Herein, we describe the development of an intermolecular C−H alkenylation of enamides with the feedstock chemical vinyl acetate to access diverse functionalized ketones. Enamides derived from various cyclic and acyclic ketones reacted efficiently, and a number of sensitive functional groups were tolerated. In this iridium‐catalyzed transformation, two structurally and electronically similar alkenes—enamide and vinyl acetate—underwent selective cross‐coupling through C−H activation. No reaction partner was used in large excess. The reaction is also pH‐ and redox‐neutral with HOAc as the only stoichiometric by‐product. Detailed experimental and computational studies revealed a reaction mechanism involving 1,2‐Ir‐C migratory insertion followed bysyn‐β‐acetoxy elimination, which is different from that of previous vinyl acetate mediated C−H activation reactions. Finally, the alkenylation product can serve as a versatile intermediate to deliver a variety of structurally modified ketones.

Applications of TEMPO^.catalysis for the development of redox‐neutral transformations are rare. Reported here is the first TEMPO^.‐catalyzed, redox‐neutral C−H di‐ and trifluoromethoxylation of (hetero)arenes. The reaction exhibits a broad substrate scope, has high functional‐group tolerance, and can be employed for the late‐stage functionalization of complex druglike molecules. Kinetic measurements, isolation and resubjection of catalytic intermediates, UV/Vis studies, and DFT calculations support the proposed oxidative TEMPO^./TEMPO⁺redox catalytic cycle. Mechanistic studies also suggest that Li₂CO₃plays an important role in preventing catalyst deactivation. These findings will provide new insights into the design and development of novel reactions through redox‐neutral TEMPO^.catalysis.

An N‐heterocyclic‐carbene‐ligated 3‐benzoborepin with a bridged structure has been synthesized by double radicaltrans‐hydroboration of benzo[3,4]cycloundec‐3‐ene‐1,5‐diyne with an N‐heterocyclic carbene borane. The thermal reaction of the NHC‐ligated borepin at 150 °C gives an isolable NHC‐boranorcaradiene. Experiments and density functional theory calculations support a mechanism whereby the borepin initially rearranges to a boranorcaradiene by a thermal 6π‐electrocyclic reaction. This is followed by 1,5‐boron shift to give a rearranged boranorcaradiene. This shift occurs with stereoinversion at boron through a transition state with open‐shell diradical character. This is the first example of the isolation of a boranorcaradiene from a thermal reaction of a borepin.

In nature, enzymatic pathways generate C_aryl−C(O) bonds in a site-selective fashion. Synthetically, C_aryl−C(O) bonds are synthesised in organometallic reactions using prefunctionalized substrate materials. Electrophilic routes are largely limited to electron-rich systems, non-polar medium, and multiple product formations with a limited scope of general application. Herein we disclose a directedpara-selective ketonisation technique of arenes, overriding electronic bias and structural congestion, in the presence of a polar protic solvent. The concept of hard–soft interaction along with in situ activation techniques is utilised to suppress the competitive routes. Mechanistic pathways are investigated both experimentally and computationally to establish the hypothesis. Synthetic utility of the protocol is highlighted in formal synthesis of drugs, drug cores, and bioactive molecules.

Cooperative catalysis enables the direct enantioselective α‐allylation of linear prochiral esters with 2‐substituted allyl electrophiles. Critical to the successful development of the method was the recognition that metal‐centered reactivity and the source of enantiocontrol are independent. This feature is unique to simultaneous catalysis events and permits logical tuning of the supporting ligands without compromising enantioselectivity.

The trifluoromethoxy (OCF₃) radical is of great importance in organic chemistry. Yet, the catalytic and selective generation of this radical at room temperature and pressure remains a longstanding challenge. Herein, the design and development of a redox‐active cationic reagent (1) that enables the formation of the OCF₃radical in a controllable, selective, and catalytic fashion under visible‐light photocatalytic conditions is reported. More importantly, the reagent allows catalytic, intermolecular C−H trifluoromethoxylation of a broad array of (hetero)arenes and biorelevant compounds. Experimental and computational studies suggest single electron transfer (SET) from excited photoredox catalysts to1resulting in exclusive liberation of the OCF₃radical. Addition of this radical to (hetero)arenes gives trifluoromethoxylated cyclohexadienyl radicals that are oxidized and deprotonated to afford the products of trifluoromethoxylation.

The regioselective conversion of C−H bonds into C−Si bonds is extremely important owing to the natural abundance and non‐toxicity of silicon. Classical silylation reactions often suffer from poor functional group compatibility, low atom economy, and insufficient regioselectivity. Herein, we disclose a template‐assisted method for the regioselectivepara silylation of toluene derivatives. A new template was designed, and the origin of selectivity was analyzed experimentally and computationally. An interesting substrate–solvent hydrogen‐bonding interaction was observed. Kinetic, spectroscopic, and computational studies shed light on the reaction mechanism. The synthetic significance of this strategy was highlighted by the generation of a precursor of a potential lipophilic bioisostere of γ‐aminobutyric acid (GABA), various late‐stage diversifications, and by mimicking enzymatic transformations.