C-C, C-O, C-N bond formation on sp2 carbon by Pd(II)-catalyzed reactions involving oxidant agents.

Amine radical cations are highly useful reactive intermediates in amine synthesis. They have displayed several modes of reactivity leading to some highly sought-after synthetic intermediates including iminium ions, α-amino radicals, and distonic ions. One appealing method to access amine radical cations is through one-electron oxidation of the corresponding amines under visible light photoredox conditions. This approach and subsequent chemistries are emerging as a powerful tool in amine synthesis. This article reviews synthetic applications of amine radical cations produced by visible light photocatalysis.

https://www.beilstein-journals.org/bjoc/content/pdf/1860-5397-9-234.pdf

The chemistry of amine radical cations produced by visible light photoredox catalysis

A variety of substituted isocoumarins and α-pyrones are readily prepared in excellent yields under very mild reaction conditions by the reaction of o-(1-alkynyl)benzoates and (Z)-2-alken-4-ynoates with ICl, I2, PhSeCl, p-O2NC6H4SCl, and HI. This methodology accommodates various alkynyl esters and has been successfully extended to the synthesis of polycyclic aromatic and biaryl compounds.

Synthesis of Isocoumarins and α-Pyrones via Electrophilic Cyclization

A number of 3,4-disubstituted isocoumarins and polysubstituted alpha-pyrones have been prepared in good yields by treating halogen- or triflate-containing aromatic and alpha,beta-unsaturated esters, respectively, with internal alkynes in the presence of a palladium catalyst. Synthetically, the methodology provides an especially simple and convenient, regioselective route to isocoumarins and alpha-pyrones containing aryl, silyl, ester, tert-alkyl, and other hindered groups. The reaction is believed to proceed through a seven-membered palladacyclic complex in which the regiochemistry of the reaction is controlled by steric factors. A number of 3,4-disubstituted isocoumarins and polysubstituted alpha-pyrones have been prepared in good yields by treating halogen- or triflate-containing aromatic and alpha,beta-unsaturated esters, respectively, with internal alkynes in the presence of a palladium catalyst. Synthetically, the methodology provides an especially simple and convenient regioselective route to isocoumarins and alpha-pyrones containing aryl, silyl, ester, tert-alkyl, and other hindered groups. The reaction is believed to proceed through a seven-membered palladacyclic complex in which the regiochemistry of the reaction is controlled by steric factors.

Synthesis of Isocoumarins and alpha-Pyrones via Palladium-Catalyzed Annulation of Internal Alkynes.

Palladium-catalysed reactions of alcohols. Part C: Formation of ether linkages

Palladium‐catalyzed synthesis of isocoumarin and 1‐isoquinolinone derivatives

Manganese(III) acetate oxidation of 1-acetylindole derivatives

In the presence of copper(I) chloride, the palladium catalyzed oxidation of methyl 2-ethenylbenzoates and 2-ethenylbenzamides have been studied. This reaction was used to form isocoumarins and 1-isoquinolinones.

Palladium-Catalyzed Synthesis of Isocoumarin and 1-Isoquinolinone Derivatives.

In the presence of malonic acid, the reaction of 1-acetylindole (2) with manganese(III) acetate resulted in the formation of 4-acetyl-3,3a,4,8b-tetrahydro-2H-furo[3,2-b]indol-2-one (5). The same reaction of 1-acetyl-2,3-dimethylindole yielded a mixture of 2-acetoxymethyl-1-acetyl-3-methylindole (7) and 4-acetyl-3a,8b-dimethyl-3,3a,4,8b-tetrahydro-2H-furo[3,2-b]indol-2-one (8), furthermore, the oxidation of 1-acetylindoline proceeded to the formation of 2, 5 and 1-acetylindoline-5-carboxylic acid (9)

Kunihiro Kohei

Papers

Palladium‐catalyzed synthesis of isocoumarin and 1‐isoquinolinone derivatives

Manganese(III) acetate oxidation of 1-acetylindole derivatives

Palladium-Catalyzed Synthesis of Isocoumarin and 1-Isoquinolinone Derivatives.

Manganese(III) Acetate Oxidation of 1-Acetylindole Derivatives.