Radical-Mediated α- tert -Alkylation of Aldehydes by Consecutive 1,4- and 1,3-(Benzo)thiazolyl Migrations

In this study, we developed a light-induced difunctionalization of [1.1.1]propellane with heteroaryl sulfones acting as difunctional reagents, allowing the introduction of alkyl and heteroaryl units across bicyclo[1.1.1]pentane frameworks. It features a broad substrate scope and can be used to functionalize structurally complex natural products. Mechanistic investigations indicate the Cs 2 CO 3 promoted homolytic cleavage of heteroaryl sulfone C−S bonds by light. Moreover, the benzothiazolyl moiety in the products can serve as a formyl precursor, indicating the robust transformability of the products, owing to the ability of aldehydes to undergo a wide variety of organic transformations.

Light-Induced, Cs₂CO₃ Promoted C–S Cleavage of Heteroaryl Sulfones for Benzyl Heteroarylation of [1.1.1]Propellane

Jiang,

Dong,

Wang

et al. 2024

Visible-Light-Induced α-Arylation of Ketones with (Hetero)aryl Halides

Liang,

Wang,

Xue

et al. 2024

An enamine-mediated photoredox catalyzed C-(sp 2 )−C(sp 3 ) cross-coupling of dual radical precursors for the arylation of ketone is presented in this Letter. These reactions led to the formation of an enamine by using pyrrolidine to functionalize the C(sp 3 )−H bond in ketone substrates, which could be smoothly converted to α-arylated ketones with inert aryl bromides and even aryl chlorides in moderate to good yields under mild reaction conditions. The photocatalytically induced C(sp 2 )− C(sp 3 ) cross-coupling between unactivated noncyclic ketones and aryl halides was achieved, and multiple carbonyl α-arylated backbones containing various natural products and drug molecules were successfully constructed.

EDA-Enabled Three-Component Polarity-Crossover Cyclization: Modular Installation of Fully Substituted γ-Lactams

Yan,

Liu,

Chen

et al. 2024

A photoinduced three-component radical additionaminalization cascade was accomplished, enabling rapid assembly of a wide range of densely functionalized γ-lactams. Key to this transformation is the electron-donor-acceptor (EDA) generation of enamine and in situ trapping of an iminium intermediate with bromodifluoroacetamide. This rationally designed protocol fully takes advantage of the polarity crossover (enamine-iminium) in the process, providing the modular assembly of previously inaccessible scaffolds. The reaction proceeds under mild reaction conditions with excellent regio-and diastereoselectivity, which is amenable to structurally varied substrates and pharmaceuticals.