A wide range of halogenated bicyclo[1.1.1]pentanes are accessed by functional group tolerant radical ring-opening of tricyclo[1.1.1.01,3]pentane, using triethylborane as initiator.

Photoredox catalysis has transformed the landscape of radical-based synthetic chemistry. Additions of radicals generated through photoredox catalysis to carbon−carbon πbonds are well-established; however, this approach has yet to be applied to the functionalization of carbon−carbon σ-bonds. Here, we report the first such use of photoredox catalysis to promote the addition of organic halides to the carbocycle [1.1.1]propellane; the product bicyclo[1.1.1]pentanes (BCPs) are motifs of high importance in the pharmaceutical industry and in materials chemistry. Showing broad substrate scope and functional group tolerance, this methodology results in the first examples of bicyclopentylation of sp 2 carbon−halogen bonds to access (hetero)arylated BCPs, as well as the functionalization of nonstabilized sp 3 radicals. Substrates containing alkene acceptors allow the single-step construction of polycyclic bicyclopentane products through unprecedented atom transfer radical cyclization cascades, while the potential to accelerate drug discovery is demonstrated through late-stage bicyclopentylations of natural productlike and druglike molecules. Mechanistic investigations demonstrate the importance of the photocatalyst in this chemistry and provide insight into the balance of radical stability and strain relief in the reaction cycle.

A general, cost-effective and sustainable replacement for silver in palladium catalysed direct arylations of C(sp2)–H and C(sp3)–H bonds.

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ortho-Arylation of ortho-substituted benzoic acids is a challenging process due to the tendency of the reaction products toward Pd-catalyzed protodecarboxylation. A simple method for preventing decarboxylation in sterically hindered benzoic acids is reported. The method described represents a reliable and broadly applicable entry to 2-aryl-6-substituted benzoic acids.

A cooperative multicatalytic cascade sequence involving isocyanoacetates and α,β-unsaturated ketones is described for the enantioselective synthesis of 2,3-dihydropyrroles. The key to promoting the multistep asymmetric reaction is the combination of cinchona alkaloid derived organocatalysts with silver nitrate. Merging both organic and metal catalytic

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Readily available chiral primary 1,2-aminoalcohols and diamines have been explored as organocatalysts for a domino Michael-aldol reaction. Their application in this organocascade process afforded cyclohexanone A with high levels of reactivity (up to 91% yield) and stereoselectivity (>97 : 3 d.r., up to 93% ee). Depending on the acid cocatalyst different chiral species (cyclic secondary amines vs. acyclic primary amines) might catalyse the process. In order to shed light on the catalytic activation, several experiments were carried out and a detailed possible reaction mechanism is proposed. Theoretical studies support the stereochemical outcome of the process.