A Free Radical Cascade Difunctionalization of o ‐Vinylanilides with Simple Ketones and Esters

TBPEH-TBPB Initiate the Radical Addition of Benzaldehyde and Allyl Esters

Tert-butylperoxy-2-ethylhexanoate (TBPEH) and tert-butyl peroxybenzoate (TBPB) promote the radical acylation of allyl ester with benzaldehyde to synthesize new carbonyl-containing compounds under solvent-free and metal-free conditions. This reaction is compatible with electron-donating and halogen groups and has excellent atom utilization and chemical selectivity. Furthermore, the synthetic compounds can further apply to the preparation of lactone, piperidine, tetrazole and oxazole.

Aerial Oxygen-Driven Selenocyclization of O-Vinylanilides Mediated by Coupled Fe3+/Fe2+ and I2/I− Redox Cycles

In the past decade, selenocyclization has been extensively exploited for the preparation of a wide range of selenylated heterocycles with versatile activities. Previously, selenium electrophile-based and FeCl3-promoted methods were employed for the synthesis of selenylated benzoxazines. However, these methods are limited by starting material availability and low atomic economy, respectively. Inspired by the recent catalytic selenocyclization approaches based on distinctive pathways, we rationally constructed an efficient and greener double-redox catalytic system for the access to diverse selenylated benzoxazines. The coupling of I2/I− and Fe3+/Fe2+ catalytic redox cycles enables aerial O2 to act as the driving force to promote the selenocyclization. Control and test redox experiments confirmed the roles of each component in the catalytic system, and a PhSeI-based pathway is proposed for the selenocyclization process.

C-centered radical-initiated cyclization by directed C(sp3)–H oxidative functionalization

C(sp3)–H functionalization is attracting constant attention. This review emphasizes C-centered radicals initiated cyclization strategies by directed C(sp3)–H oxidative functionalization since 2012.

Iron-catalyzed domino coupling reactions of π-systems

The development of environmentally benign, inexpensive, and earth-abundant metal catalysts is desirable from both an ecological and economic standpoint. Certainly, in the past couple decades, iron has become a key player in the development of sustainable coupling chemistry and has become an indispensable tool in organic synthesis. Over the last ten years, organic chemistry has witnessed substantial improvements in efficient synthesis because of domino reactions. These protocols are more atom-economic, produce less waste, and demand less time compared to a classical stepwise reaction. Although iron-catalyzed domino reactions require a mindset that differs from the more routine noble-metal, homogenous iron catalysis they bear the chance to enable coupling reactions that rival that of noble-metal-catalysis. This review provides an overview of iron-catalyzed domino coupling reactions of π-systems. The classifications and reactivity paradigms examined should assist readers and provide guidance for the design of novel domino reactions.

Cascade Radical Annulation of 2-Alkynylthio(seleno)anisoles with Acetone or Acetonitrile: Synthesis of 3-Acetomethyl- or Cyanomethyl-Substituted Benzothio(seleno)phenes

An efficient method for the direct preparation of 3-aceto(cyano)methyl-substituted benzothio(seleno)phenes has been achieved through C(sp³)-H bond activation of easily available acetone or acetonitrile and cascade radical cyclization reaction. In this cascade radical cyclization reaction, C(sp²)-C(sp³) and C(sp²)-S bonds, as well as benzenethio(seleno)phene skeletons, can be built along with the cleavage of the C(sp³)-S bond, demonstrating the high step-economics and efficiency of this approach.

Iron-promoted free radical cascade difunctionalization of unsaturated benzamides with silanes

An efficient cascade difunctionalization of unsaturated benzamides with silanes was developed for the synthesis of various silylated dihydroisoquinolinones and 1,3-isoquinolinediones.