Volume 1 Issue 6, June 2022

Alkyne metathesis has been used to prepare the carbon allotrope γ-graphyne, which is composed equally of sp- and sp²-hybridized carbon atoms. The carbon sheets are stacked in an ABC staggered interlayer arrangement and can be exfoliated like graphene.

Click chemistry is widely used in organic and materials chemistry. Now, a divergent sulfur(VI) fluoride exchange process provides access to a range of synthetically valuable vinylic and acetylenic sulfoximine products.

The Kolbe electrolysis is a transformation renowned for forging C(sp³)–C(sp³) bonds. However, it is challenging to selectively make cross-products — that is, form new bonds from different partners — using this reaction. Now, a nickel-catalysed ‘reductive Kolbe’ reaction enables a decarboxylative cross-coupling approach.

Converting simple building blocks into enantiopure amines is an important synthetic transformation. Now, a biocatalyst has been discovered that catalyses two reductive steps within a single active site, and can synthesize a range of amine targets from ene–one starting materials.

The synthesis of phosphorus-rich analogues of carbon-based compounds is a desirable but challenging endeavour. Now, the synthesis of the anion [Fe(P₄)₂]^2– is reported, which so far is the most similar all-phosphorus relative to well-known ferrocene, [Fe(η⁵-C₅H₅)₂].

Accessing reactive ketyl-type radicals in mild and controllable ways represents an ambitious target. A study now reports a multicomponent palladium-photocatalysed reaction between aldehydes, 1,3-butadiene and various nucleophiles that affords complex homoallylic alcohols through ketyl-type radicals.

Catalytic asymmetric transformations of quinone methides and indole imine methides involve catalysts such as chiral Brønsted acids, Lewis acids and bases as well as transition metal complexes. In this Review, these asymmetric transformations are discussed with a focus on reaction pathways and activation modes.

Alkaline earth elements are among the most abundant and cost-effective metals in the toolbox of synthetic chemists and investigations of their structures and bonding have led to fascinating discoveries. This Review discusses the emerging synthetic chemistry and unusual redox chemistry of low-oxidation-state Be, Mg and Ca complexes.

The synthesis of graphynes has often been limited to using irreversible coupling reactions that are likely to result in materials that lack long-range order. Now, a periodically sp–sp²-hybridized carbon allotrope, γ-graphyne, is prepared using a reversible dynamic alkyne metathesis and managing the balance between kinetic and thermodynamic control. This material’s interlayer stacking and folding behaviour are also revealed.

The coupling of sulfonimidoyl fluorides and alkynes using sulfur(VI) fluoride exchange (SuFEx) reactions has not been available because of the intrinsic reactivity of the π component. Now, a divergent SuFEx process between sulfonimidoyl fluorides and alkynes to produce vinylic or acetylenic sulfoximines is reported. Mechanistic studies reveal the origins of the vinylic sulfoximines, and several synthetic transformations of the products demonstrate the utility of the process.

Ketyl radicals can be used in a range of reactions, but their generation often requires harsh conditions and a large excess of reductants. Now, a multicomponent, palladium-photocatalysed reaction between aldehydes, 1,3-butadiene and N, S, O and C nucleophiles to build architecturally complex homoallylic alcohols is reported wherein ketyl-type radicals are generated under mild conditions.

Methods for the hydrofluoroalkylation of alkenes often require expensive reagents and have limited reaction scope. Now, a photoinduced manganese-catalysed hydrofluoroalkylation is reported, providing an array of fluoroalkyl-containing products from fluoroalkyl halides. Mechanistic studies reveal that the bidentate phosphine ligand plays a key role in atom transfer processes and increases the stability and lifetime of the metalloradical intermediate.

The selective functionalization of C=C bonds of alkenes is well studied, however, regio- and enantioselective transformations of the allylic C–H bond of unactivated alkenes are relatively underexplored. Now, a palladium-catalysed branch-selective and enantioselective allylic C−H alkylation of α-alkenes is reported. The process tolerates a wide range of α-alkenes, from chemical feedstocks to bioactive α-alkenes