The use of low-cost manganese(II) bromide (MnBr2) and tetramethylethylenediamine (TMEDA) catalyzes the cross coupling of (bis)pinacolatodiboron with a wide range of alkyl halides, demonstrating the first manganese-catalyzed coupling with alkyl electrophiles. This method allows access to primary, secondary, and tertiary boronic esters from the parent chlorides, which were previously inaccessible as coupling partners. The reaction proceeds in high yield with as little as 1000 ppm catalyst loading, while 5 mol % can provide high yields in as little as 30 min. Finally, radical-clock experiments revealed that at 0 °C direct borylation outcompetes alternative radical processes, thereby providing synthetically useful, temperature-controlled reaction outcomes.

This communication describes a mild, amide-directed fluorination of benzylic, allylic, and unactivated C–H bonds mediated by iron. Upon exposure to a catalytic amount of iron(II) triflate (Fe(OTf)2), N-fluoro-2-methylbenzamides undergo chemoselective fluorine transfer to provide the corresponding fluorides in high yield. The reaction demonstrates broad substrate scope and functional group tolerance without the use of any noble metal additives. Mechanistic and computational experiments suggest that the reaction proceeds through short-lived radical intermediates with F-transfer mediated directly by iron.

Using 8-aminoquinoline-based aryl carboxamides, the direct ortho-alkylation can be achieved in high yields in the presence of an iron source, 1,2-bis(diphenylphosphino)ethane (dppe) and phenylmagnesium bromide. The reactions proceed without overalkylation and provide high levels of regioselectivity. The benzylation reactions can be performed in air with reagent-grade THF, while the alkylation works well with unactivated secondary bromides and iodides in 2-methyltetrahydrofuran. Moreover, the reactions only require 5–10 min.

The use of low-cost iron(III) acetoacetate (Fe(acac)3) and tetramethylethylenediamine (TMEDA) enables the direct cross-coupling of alkyl halides with bis(pinacolato)diboron. This approach allows for the borylation of activated or unactivated primary, secondary, and tertiary bromides. Moreover, even the borylation of benzylic or allylic chlorides, tosylates, and mesylates are possible. The reactions proceed under mild conditions at room temperature and show broad functional-group compatibility and “robustness” as measured by a modified Glorius robustness screen.

The iron-catalyzed coupling of aryl sulfamates and tosylates with aryl Grignard reagents is reported for the first time. The methodology employs air-stable, low-cost FeF3·3H2O and the N-heterocyclic carbene ligand IPr·HCl as the preligand to form a long-lived catalyst upon treatment with aryl Grignards. The reaction provides a range of cross-coupled products in good-to-excellent yields. In contrast to previous reports with aryl chlorides, these reactions proceed with low levels of Grignard homocoupling regardless of the iron source.

A simple, iron-based catalytic system allows for the inter- and intramolecular arylation of unactivated secondary alcohols. This transformation expands the substrate scope beyond the previously required activated alcohols and proceeds under mild reaction conditions, tolerating air and moisture. Furthermore, the use of an enantioenriched secondary alcohol provides an enantioenriched product for the intramolecular reaction, thereby offering a convenient approach to nonracemic products.

A new route to trisubstituted olefins through a palladium-catalyzed alkyne insertion/reduction reaction with unactivated alkyl iodides is reported. The reaction proceeds under mild conditions and tolerates a range of functional groups and substitution patterns. Preliminary mechanistic inquiry suggests that the transformation may proceed through a hybrid radical/organometallic pathway.

The iron-catalyzed cross-coupling of aryl sulfamates and tosylates has been achieved with primary and secondary alkyl Grignards. This study of iron-catalyzed cross-coupling reactions also examines the isomerization and β-hydride elimination problems that are associated with the use of isopropyl nucleophiles. While a variety of iron sources were competent in the reaction, the use of FeF3•3H2O was critical to minimize nucleophile isomerization.

The Pd-catalyzed TBHP-mediated Wacker-type oxidation of internal alkenes is reported. The reaction uses 2-(4,5-dihydro-2-oxazolyl)quinoline (Quinox) as ligand and TBHP(aq) as oxidant to deliver single ketone constitutional isomer products in a predictable fashion from electronically biased olefins. This methodology is showcased through its application on an advanced intermediate in the total synthesis of the antimalarial drug artemisinin.

A palladium-catalyzed alkyne insertion/Suzuki reaction with unactivated alkyl iodides is described. Under the reaction conditions, selective migratory insertion of alkynes avoids β-hydride elimination and provides a facile synthesis of stereodefined, tetrasubstituted olefins. The transformation offers broad substrate scope for both the alkyl iodide and boron nucleophile. Mechanistic studies have revealed inversion of the stereocenter for the carbon bearing the iodide.

Malaria represents one of the most medically and economically debilitating diseases present in the world today. Fortunately, there exists a highly effective treatment based on the natural product artemisinin. Despite the development of several synthetic approaches to the natural product, a streamlined synthesis that utilizes low-cost chemical inputs has yet to materialize. Here we report an efficient, cost-effective approach to artemisinin. Key to the success of the strategy was the development of mild, complexity-building reaction cascades that allowed the use of readily available, affordable cyclohexenone as the key starting material.

The reduction of a palladium enolate prior to β-hydride elimination provides a unique reaction for the synthesis of the hydroazulene ring system. When combined with a transannular epoxide rearrangement cascade, the reductive-Heck reaction allows rapid entry to the oxo-bridged guaiane core of the englerins.