Van Ha Nguyen

Mn(III)-based reactions of alkenes and alkynes with thiols. An approach toward substituted 2,3-dihydro-1,4-oxathiins and simple route to (E)-vinyl sulfides

Abstract The first example using manganese(III) acetate in the reaction of 1,1-diarylethenes with α-mercaptoketones was examined. A mixture of the ethenes and α-mercaptoketones was treated with manganese(III) acetate in acetic acid, affording cycloaddition products in moderate yields, together with substituted products. The reaction may involve the formation of a carbocation and subsequent cyclization to give the substituted 2,3-dihydro-1,4-oxathiin 3 . A similar reaction with thioglycolic acid gave 1,4-oxathiolan-2-one 7 . While thiyl radicals easily formed by manganese(III) oxidation with ethanethiol or benzenethiol reacted with alkynes to give preferentially ( E )-vinyl sulfides 10 in quantitative yields.

Mn(III)-Induced molecular oxygen trapping reaction of alkenes with 2,3-pyrrolidinedione derivatives. A novel entry to 1-hydroxy-8-aza-2,3-dioxabicyclo[4.3.0]nonan-9-ones

Abstract Molecular oxygen trapping reaction of alkenes with 2,3-pyrrolidinedione derivatives was developed using a Mn(III)-induced oxidation system. Alkenes and 2,3-pyrrolidinediones were treated with manganese(III) acetate in acetic acid under a stream of dry air, giving 1-hydroxy-8-aza-2,3-dioxabicyclo[4.3.0]nonan-9-ones in good yields. The reaction involved molecular oxygen trapping of radicals which were formed by the addition of pyrrolidinedione radicals induced by Mn(III) to alkenes.

Catalytic oxidation of 4-piperidone-3-carboxylates with manganese(III) acetate in the presence of 1,1-disubstituted alkenes

Abstract The manganese(III) acetate-catalyzed cycloperoxidation of 4-piperidone-3-carboxylates with 1,1-disubstituted alkenes is described. The 4-piperidone-3-carboxylates reacted with 1,1-disubstituted alkenes in the presence of a catalytic amount of manganese(III) acetate in air at 23°C to give 1-hydroxy-8-aza-2,3-dioxabicyclo[4.4.0]decane-6-carboxylates in good to moderate yields. The crystal structure of the azabicyclic peroxides was determined by an X-ray single crystal analysis. The oxidation of the 4-piperidone-3-carboxylates with 1,1-diphenylethene using a stoichiometric amount of manganese(III) acetate gave ethenyl- and ethyl-substituted 4-piperidones and 6-hydroxy-3-aza-7-oxabicyclo[4.3.0]nonane-1-carboxylate, which was the same as the product obtained from the hydrogenolysis of the 1-hydroxy-8-aza-2,3-dioxabicyclo[4.4.0]decane-6-carboxylate.

Convenient synthesis of 3-cyano-4,5-dihydrofurans and 4-cyano-1,2-dioxan-3-ols using acylacetonitrile building block

Abstract Acylacetonitriles were easily oxidized with manganese(III) acetate in acetic acid to form the corresponding acylcyanomethyl radicals, which attacked alkenes at reflux temperature to give new 3-cyano-4,5-dihydrofurans and at the room temperature under air to yield new 4-cyano-1,2-dioxan-3-ols in good yields.