Recent developments in the synthesis of the isoquinoline-1,3(2H,4H)-dione by radical cascade reaction

In recent years, isoquinoline-1,3(2H,4H)-dione compounds have attracted extensive attention from synthetic chemists, with the aim of finding simple, mild, green and efficient synthetic methods. In this review, we summarize the diverse range of synthetic methods employing acryloyl benzamides as key substrates to furnish isoquinoline-1,3-diones using different radical precursors, such as those containing carbon, sulphur, phosphorus, nitrogen, silicon and bromine. This will stimulate the interest of readers to engage in research in this field.

Recent advances in acyl radical enabled reactions between aldehydes and alkenes

Radical-mediated functionalization of alkenes has been emerging as an elegant and straightforward protocol to increase molecule complexity. Moreover, the abstraction of a hydrogen atom from aldehydes to afford acyl radicals has evolved as a rising star due to its high atom-economy and the ready availability of aldehydes. Considering the great influence and synthetic potential of acyl radical enabled reactions between aldehydes and alkenes, we provide a summary of the state of the art in this field with a specific emphasis on the working models and corresponding mechanisms. The discussion is divided according to the kind of alkenes and reaction type.

Visible-light-promoted acyl radical cascade reaction for accessing acylated isoquinoline-1,3(2H,4H)-dione derivatives

A visible-light-promoted radical acylation/cyclization cascade reaction of N-methacryloylbenzamides with α-keto acids was developed to construct acylated isoquinoline-dione derivatives.

Visible-light induced di- and trifluoromethylation of N-benzamides with fluorinated sulfones for the synthesis of CF2H/CF3-containing isoquinolinediones

A photocatalytic radical di- or trifluoromethylation/cyclization of methacryloyl benzamides with fluorinated sulfones provided an efficient route to CF₂H/CF₃-containing isoquinoline-1,3(2H,4H)-diones.

Oxidative decarbonylative coupling of aliphatic aldehydes with methacryloyl benzamides to generate isoquinoline-1,3(2H,4H)-diones

Alkyl-substituted isoquinoline-1,3(2H,4H)-diones were prepared by coupling of N-alkyl-N-methacryloylbenzamides and aliphatic aldehydes through subsequent decarbonylation, radical addition and cyclization processes.

Aerobic thiyl radical addition/cyclization of N-methacryloyl benzamides for the synthesis of isoquinoline-1,3(2H,4H)-dione derivatives

A highly effective dioxygen-triggered oxidative thiyl radical addition/cyclization of N-methacryloylbenzamides was explored. This method provides convenient access to a variety of useful sulfide-containing 4,4-disubstituted isoquinoline-1,3-diones.

Addition of nitrogen dioxide to carbon–carbon double bond followed by a cyclization to construct nitromethylated isoquinolinediones

4-(Nitromethyl)isoquinoline-1,3(2H,4H)-diones were synthesized via a tandem nitration/cyclization reaction of N-alkyl-N-methacryloyl benzamides using CO₂ as the nitro source.

Copper-Catalysed Couplings of N-Substituted-N-Methacryloylbenzamides with Isopropanol to Generate Hydroxyl-Substituted Isoquinoline-1,3(2H,4H)-Dione Derivatives

A copper-catalysed free-radical cascade cyclisation of N-substituted- N-methacryloylbenzamides with isopropanol has been developed, which allows convenient access to various hydroxyl-substituted isoquinoline-1,3(2 H,4 H)-dione derivatives.

Visible light-promoted synthesis of 4-(sulfonylmethyl)isoquinoline-1,3(2H,4H)-diones via a tandem radical cyclization and sulfonylation reaction

4-(Sulfonylmethyl)isoquinoline-1,3(2H,4H)-diones were synthesized via a visible-light-promoted cyclization and sulfonylation reaction catalyzed by fac-Ir(ppy)₃.

One-pot cascade synthesis of N-methoxyisoquinolinediones via Rh(iii)-catalyzed carbenoid insertion C–H activation/cyclization

A mild and efficient method for one-pot synthesis of N-methoxyisoquinolinediones via Rh(iii)-catalyzed carbenoid insertion C–H activation/cyclization has been developed.