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Oxidative free-radical cyclizations of acetoacetates 1 , 8 , 17 , and 20 with Mn(OAc) 3 ·2H 2 and Cu(OAc) 2 ·H 2 O in acetic acid provide cycloheptenes and cyclooctenes in moderate to good yield. Tandem cyclizations of 28 , 35 and 51 provide bicyclo[4.2.1]nonanes, bicyclo[5.2.1]decanes, bicyclo[5.3.0]decanes and bicyclo[6.3.0]undecanes.

Oxidation of cyclohexene by (tetraphenylporphyrinato)manganese(III) acetate (Mn(TPP)OAc) and sodium hypochlorite as oxidant has been studied in a two-phase water-dichloromethane system in the presence of a phase transfer reagent. A kinetic study with this system reveals the following features: (1) the main product of the reaction (yield ⩾ 80%) is 1,2-epoxy-cyclohexane; (2) in the presence of excess oxidant the reaction is zero order in cyclohexene; (3) the reaction order in Mn(III) concentration decreases from 1 to ≈ 0 with increasing concentration of this catalyst; (4) the reaction order in hypochlorite decreases from 1 to 0 with increasing concentration of this reagent; (5) pyridine and substituted pyridines enhance the reaction rate. A Hammett treatment of the rate data for various substituted pyridines gives a p-value of −1.00; (6) anchoring of Mn(TPP)OAc onto poly(vinylpyridine) or a polymer of an isocyanide, , increases the reaction rate by a factor of 1.5 – 6.0. Based on these findings and on evidence from the literature, a mechanism for the epoxidation of cyclohexene is proposed. The key intermediate is an oxo-manganese(V) complex, which is formed from Mn(III) and hypochlorite in a pyridine-catalyzed step. The Mn(V) species may react in 2 ways: either with substrate to give epoxide or with Mn(III) to form a μ-oxo-manganese(IV) dimer. The latter route is suppressed when the catalyst is anchored to the polymeric support.

Use of manganic acetate as oxidant permits efficient trifluoroacetoxysulphenylation of unsaturated nitriles with organic disulphides. The adducts in a cobaltous chloride promoted hydrolysis afford alkyl- or aryl-thio substituted lactones.

Additional mechanistic and synthetic details concerning the formation of nitroalkylated aromatic products from the reaction of nitroalkanes with manganese(III) acetate and an aromatic compounds are presented. A large isotope effect (k/sub H//k/sub D/ = 4.02-4.20) was found for both manganese(III)-and cerium(IV)-promoted nitromethylations with nitromethane-d/sub 3/ while no isotope effect (k/sub H//k/sub D/ = 1.05) was observed with benzene-d/sub 6/. This indicated that deprotonation (most likely from an aci radical cation) to the nitromethyl radical is the slow step while subsequent rearomatization of a sigma-radical complex occurs rapidly. Somewhat more convenient methods of activating the manganese(III) acetate promotor were found. However, attempts to find cooxidants or other additives which could improve this process met with only limited success. The reaction of either toluene or benzene with nitroethane or the nitropropanes and manganese(III) acetate in refluxing acetic acid gave much poorer fields (3 to 8%) of the corresponding nitroalkylated products. Incorporation of sodium acetate into these systems completely elimiated the aromatic substituttion products and formed ..cap alpha..-nitroalkyl acetates instead. Implications of this finding on the mechanism for the generation of nitroalkyl radicals are discussed.

Intramolecular lactone annulation of activated carboxylic acids onto olefins by manganese(III) acetate yields bicyclo[3.3.0] and [4.3.O]lactones.

The reaction of 4′-methoxyacetophenone with manganese(III) acetate in the presence of ammonium chloride yielded 2-chloro-4′-methoxyacetophenone (2a) and 2,2-dichloro-4′-methoxyacetophenone (3a). The reaction of 2a with these reagents gave 3a, 4′-methoxy-2,2,2-trichloroacetophenone, and 1,4-bis(4-methoxyphenyl)-2,2,3,3-tetrachloro-1,4-butanedione (8a). The reactions of 2a and 2-bromoacetophenone with manganese (III) acetate yielded the corresponding 2,3-dihalo-1,4-diphenyl-1,4-butanediones, 1,4-diphenyl-2-halo-2-butene-1,4-diones, 2,3-dihalo-2-butene-1,4-diones, 2,2-dibromoacetophenone, and 8a. The reaction pathways are discussed.

The oxidation of eight (E)-α-phenylcinnamic acids with manganese(III) acetate in boiling acetic acid containing acetic anhydride gave 3-phenylcoumarins, 3-phenyl-l-oxaspiro[4.5]deca-3,7,9-triene-2,6-diones, 2-phenylbenzofurans, 3-(acetoxymethyl)-2-phenylbenzofurans, 3-formyl-2-phenylbenzofuran, 2-acetoxy-2-phenyl-3 (2H)-benzofuranones, (Z)-α-acetoxystilbenes, 2-acetoxy-1,2-diphenylethanones, 5-acetoxy-4,5-diphenyl-2 (5H)-furanones, and diphenylacetylene. The reaction pathways are discussed.

The kinetics of polymerization of acrylonitrile(AN) initiated by manganese(III) acetate in the presence of glycerol was investigated in the temperature range of 30–40°C. The effect of varying the concentrations of glycerol, sulfuric acid, acetic acid, metal ion, and monomer on the rate was studied. A suitable reaction scheme and rate expression have been proposed. Termination was mutual and was caused by the combination of two growing polymer radicals.

The conditions were investigated for electrochemical generation of lead(IV) acetate in acetic acid by oxidation of lead(II) acetate on a lead dioxide electrode and on a platinum electrode. Bivalent manganese ions are quantitatively oxidized on a platinum electrode to the tervalent state in the same solvent. Coulometric titration methods for the determination of small amounts of hydroquinone in acetic acid were developed on the basis of the electrically generated oxidizing agents. Better results were obtained in titration with electrogenerated manganese(III) acetate. The titration end-point was detected by the biamperometric method. Suitable redox indicators were found.

The reaction of manganese(III) acetate with diphenyl disulphide in dichloromethane-trifluoroacetic acid in the presence of N-allylacetamide, followed by hydrolysis, affords a vicinal hydroxy sulphide. Similarly, addition to N-allyltrifluoroacetamide affords hydroxy sulphide adducts, but with different regioselectivity. N-Allylbenzamide and other unsaturated benzamides under similar conditions give cyclic products, 4,5-dihydro-1,3-oxazoles. Homoallylic amides give 5,6-dihydro-4H-1,3-oxazines. Amides derived from pent-4-enylamine give substituted pyrrolidines by cyclisation through nitrogen, but N-hex-5-enylbenzamide gives only an acyclic adduct. Unsaturated carboxylic acids and unsaturated carboxamides are transformed in good yield into lactones under similar conditions.

As part of a study designed to synthesize the proposed high temperature superconductor MoN, molybdenum powder was reacted with manganese(III) acetate and sodium azide in refluxing glacial acetic acid. No MoN was found. Instead, rapid and complete oxidative dissolution of the metal to soluble forms of Mo(VI) were observed. Removal of the azide or replacement of the azide by chloride had no qualitative effect. Other metals were studied and four groups may be discerned: (1) quantitative dissolution in cold, pure acetic acid - Mn, Fe, Co; (2) quantitative dissolution in refluxing Mn(III) solution  Cu, Mo, In, Sn; (3) partial dissolution in refluxing Mn(III) solution  Ni, V; (4) no reaction  Ti, Zr, Nb, Ta, Cr, W, Re, Rh, Ru, and Pt. Use of preformed metal nitrides, e.g. MoN 0.6 , and variation of the oxidant, e.g. replacing Mn(III) by Fe(III) or by Co(III), resulted in little qualitative change. Some unsuccessful attempts to explain this include literature periodic trends for transition metal chemistry and Pourbaix's electrochemical ‘thermodynamic and practical nobility scales’ for corrosion by aqueous media.

The reaction of 2-(methylamino)benzophenone with manganese(III) acetate afforded 5-[(o-benzoylanilino)methyl]-2-(methylamino)benzophenone, 2-aminobenzophenone, 5-formyl-2-(methylamino)benzophenone, 2-amino-5-[(o-benzoylanilino)methyl]benzophenone, 2-formamidobenzophenone, 2-amino-5-formylbenzophenone, and 2-(N-methylformamido)benzophenone. It was found that the reaction did not cause oxidative cyclization, but dimerization and conversion of N-methyl into N-formyl groups. Characterization of the products, the detailed oxidation mechanism, and the effects of the additives are discussed.

A two step route to highly substituted tetralones via Mn(III) oxidation and cyclization has been demonstrated.

A variety of N-protected indolines can be oxidized to the corresponding indoles using manganese(III) acetate in glacial acetic acid.

La reaction est radicalaire; la nature des produits obtenus depend des substituants en α des malonates, de la stereoselectivite de l'addition intramoleculaire et de la nature du radical intermediaire

Reaction of manganic acetate with diphenyidisulplilde in dichloromethane-trifluoroacetic acid in the presence of allylic esters or amides of allylamine gives trifluoroacetoxysulphides and hence by ready hydrolysis vicinal hydroxysulphides. The regiochemical outcome can be controlled by selection of either an acetyl- or trifluoroacetyl derivative.

Lactams were produced by treatment of N,N-unsaturated dialkyl-β-oxoamides by Mn(OAc) 3 .

The review is devoted to the reactions of unsaturated systems (alkenes, alkynes, arenes, alkadienes, and alkenynes) with carbonyl compounds (aldehydes, ketones, carboxylic acids, and ?-, ?-, ?-, and ?-dicarbonyl compounds) initiated by manganese(III) acetate. Attention is concentrated on the regio- and stereo-chemistry of the interaction, the pathways leading to the stabilisation of the intermediate radical-adducts, and also the assessment of the synthetic possibilities of reactions of the given type. The bibliography includes 91 references.

The reaction of methylmalonic acid with mono- and disubstituted olefins in the presence of manganese(III) acetate yielded 2-carboxy-2-methyl-4-butanolides in moderate to good yields. The reactions of bromomalonic acid and chloromalonic acid with a variety of olefins gave 2-halo-4-butanolides and/or 2-buten-4-olides. The reaction of ethyl hydrogen malonate with olefins in the presence of manganese(III) acetate yielded 2-ethoxycarbonyl-2-buten-4-olides, 2-ethoxycarbonyl-2-ethenyl-4-butanolide, 2,7-dioxaspiro[4.4]nonane-1,6-diones, 2-ethoxycarbonyl-4-butanolide, and ethyl 3-butenoate. These reactions can be accounted for in terms of a free-radical mechanism involving substituted dicarboxymethyl radicals.

The reaction of olefins with malonamide in the presence of manganese(III) acetate gave 2-buten-4-olides and/or 1H-pyrrol-2(5H)-ones in one-step, short reaction time, and moderate yields. The product distribution can be accounted for in terms of the stabilization of the intermediate carbocation in the oxidation process. The synthetic application and limitation, and the oxidation mechanism for the formations of α,β-unsaturated γ-lactones and γ-lactams are discussed.

The conditions fox coulometric determination of small quantities of hydrazine, phenylhydrazine and isoniazid in glacial acetic acid with electrogenerated manganese(III) acetate and lead(IV) acetate were investigated. With the direct coulometric method at room temperature, good results were obtained in the determination of hydrazine and isoniazid with lead(IV) acetate and in the determination of phenylhydrazine with manganese(III) acetate. Hydrazine and isoniazid can also be determined by the coulometric back-titration method if the oxidation with manganese(III) acetate is performed at elevated temperature.

In the reaction of manganese(III) acetate with carboxylic acids and alkenes, three distinct processes have been identified which involve the alkene and two processes which are independent of alkene. A combination of product studies, rearrangements, dilution experiments and literature kinetic data allow the proposal of a unified mechanistic picture to describe these processes. Specifically, the role of α-H acidity of the carboxylic acid component, electron deficient radical additions, metal complexed organic radicals, and the importance of an oxo-centered manganese(III) triangle are discussed as they relate to the lactone annulation reaction. Single electron transfer oxidation of alkenes is described as a route toward 1,2-diacetates of alkenes within the 8.1-7.5 eV I.P. range. Three less common modes of Mn(III) reaction are discussed and compared with the two primary processes of lactone annulation and 1,2-diacetate formation.

Seven 9-xanthenones were oxidized with manganese(III) acetate to give carboxy-, dicarboxy-, (acetoxymethyl)(carboxy)-, (carboxy)(hydroxymethyl)-, and acetoxymethyl-9-xanthenones, and to yield small amounts of (carboxymethyl)(carboxy)-, carboxymethyl-, (acetoxymethyl)(carboxymethyl)-, bis(acetoxymethyl)-, and diacetoxymethyl-9-xanthenones. The carboxyl group was preferentially introduced into the peri positions and the acetoxymethyl groups were located at positions ortho to the methoxyl or methyl group. The regioselectivity and mechanism of the carboxylation reaction is discussed briefly.

2-Butenamides and 2-buten-4-olides are formed by the reaction of phenyl or 4-chlorophenyl-substituted olefins with α-cyanoacetamide in the presence of manganese(III) acetate. On the other hand, aryl substituted olefins having electron-donating groups are oxidized under similar reaction conditions to give 1,5-dihydro-2H-pyrrol-2-ones and 3-ethenyl-2-pyrrolidones. All these reactions also produce glycols or ketones which are given by the direct oxidation of these olefins with manganese(III) acetate. The question whether an intermediate carbocation in the oxidation process cyclized on an oxygen or a nitrogen atom can be explained by the hard and soft acids and bases (HSAB) concept. A possible mechanism for the formation of 2-butenamides and 2-buten-4-olides is proposed.

Oxidation of olefins by manganese(III) acetate was carried out using propionic acid as a solvent. The oxidation products obtained were propionic acid derivatives such as 2-methyl-4-propanoyloxyalkanoic acids, γ-lactones, alkanoic or alkenoic acids and propanoyloxyalkenes. Of these products, 2-methyl-4-propanoyloxyalkanoic acids underwent thermal cracking with ease to decompose into corresponding γ-lactones and propionic acid.

Under appropriate conditions manganese(III) acetate can be used as a free radical initiator to effect the addition of acid anhydrides to α-olefins in a chain reaction. This results in an efficient synthesis of straight chain or α-branched carboxylic acids. In this reaction manganese(III) acetate compares favourable with known peroxidic initiators. A mechanistic scheme accounting for the observed products is proposed.

Oxidation of benzyl cobaloximes by Mn(III) acetate leads to the formation of benzyl ethers of dimethylglyoxime.

Oxidation of p, αββ-tetramethylstyrene (I) with manganese(III) acetate gave a lactone mixture in which the presence of 4-isopropyl-4-p-tolylbutane-4-olide (V) as the major component was infrarred from its n.m.r. spectrum. The formation of this lactone (V) is attributed to the addition of carboxymethyl radical [from manganese(III) acetate] to α-isopropyl-p-methylstyrene (II), arising from (I) by double-bond isomerisation. Treatment of the lactone mixture with polyphosphoric acid furnished in high yield 4-isopropyl-7-methyl-1-tetralone (VIII), identified by independent synthesis. This cyclization involves reduction by hydride transfer.

Oxidation of allyl-and allenylcobaloximes by manganese (III) acetate yields allyl and propargyl ethers of dimethylglyoxime

The reactions of 4-methoxy-, 7-methoxy-, 6,7-dimethoxy-, and 7,8-dimethoxycoumarins with manganese(III) acetate in boiling acetic acid containing acetic anhydride gave 3-(acetoxymethyl) coumarins as the major product. The reactions of coumarin, and 6-methoxy- and 8-methoxycoumarins with manganese(III) acetate yielded a mixture of 3-(diacetoxymethyl)- and nuclear acetoxymethylated coumarins. The reaction of 7-methoxycoumarin with lead(IV) acetate gave 7-methoxy-3-methylcoumarin.

Conditions were found under which manganese(III) acetate can be electrochemically generated at a platinum anode with 100% current efficiency. It was found that even traces of 5 . Time Dependence of the Consumption of the Oxidizing Reagent in the Indirect Determination of Hydroquinone with Coulometric Generated Manganese(III) Acetate Time (min) 0 5 10 30 60 Consumption of Mn(III) (mol/mol) 2.00 1.99 2.00 2.01 2.00 water decrease the current efficiency of the generation. The observed fact ( 10 ) that small amounts of water do not interfere in direct coulometric titrations of some substances can be explained by direct anodic oxidation of substances to be determined. The possibility of a direct coulometric titration of hydroquinone with manganese(III) acetate and an indirect coulometric determination of an unconsumed excess of manganese(III) acetate via its reaction with hydroquinone was further verified. It was confirmed that under the given conditions, the coulometrically prepared reagent is sufficiently stable even for indirect determinations.

The reaction of alkyl (E)-3-phenylpropenoates with manganese(III) acetate in the presence of Cl− ions gave alkyl (Z)-2-chloro-3-phenylpropenoates and alkyl 2,3-dichloro-3-phenylpropanoates. Ethyl (E)-2,3-diphenylpropenoate yielded ethyl 2,3-dichloro-2,3-diphenylpropanoate. Alkyl 3,3-diphenylpropenoates gave mainly alkyl 2-chloro-3,3-diphenyl-propenoates. Ethyl 1-cyclohexenecarboxylate gave ethyl 1,2-dichlorocyclohexanecarboxylate. Dimethyl malonate yielded dimethyl dichloromalonate and tetramethyl 1,2-dichloro-1,1,2,2-ethanetetracarboxylate. Substituted malonates resulted in α-chloro derivatives. Methyl phenylacetates gave α-acetoxy derivatives.

Hydrazine hydrochloride and some hydrazine derivatives were titrated potentiometrically with manganese(III) acetate in glacial acetic acid. The titrations were carried out both directly and indirectly. As the direct titrations are very time consuming, the indirect titrations were found to be more practical. The number of electrons exchanged during the reaction in glacial acetic acid is different from the number exchanged if the titration is performed in aqueous media. Hydrazine, phenylhydrazine, 1,2-diphenylhydrazine, diphenylcarbazone and semicarbazide all undergo a two-electron redox reaction with manganese(III) acetate in glacial acetic acid. 4-Nitrophenylhydrazine and 2,4-dinitrophenylhydrazine undergo a redox reaction by releasing one electron under the same conditions. Diphenylcarbazide undergoes a four-electron redox reaction. The results of the acidimetric titration of hydrazine, phenylhydrazine, 4-nitrophenylhydrazine and 2,4-dinitrophenylhydrazine indirectly support the results of the redox titration of these four compounds.

The kinetics of polymerization of acrylamide (AAM) and methacrylamide (MAM) with manganese(III) acetate as thermal initiator was studied. In the temperature range between 303 and 313 K, the initial rate of polymerization follows the relation: v=k[Monomers] · [Initiator] ½ . The rate of initiation of the polymerization was determined from the rate of decomposition of manganese(III) acetate. The reactivity of the two monomers under the same conditions was compared.

Etude des reactions avec Cu(OAc) 2 et Mn(OAc) 3 d'oxo-3 allyl-2 methyl-6 heptene-6oate oxo-3 allyl-2 nonene-7oate et cyclohexene-1yl-3' propionyl-2 pentene-4oate: obtention de derives de bicyclo [3.2.1] octane, de perhydro indane et d'ethano-1,4a naphtalene

The reaction of alkyl (E)-3-phenylpropenoates with manganese(III) acetate in the presence of Cl− ions gave alkyl (Z)-2-chloro-3-phenylpropenoates and alkyl 2,3-dichloro-3-phenylpropanoates. Ethyl (E)-2,3-diphenylpropenoate yielded ethyl 2,3-dichloro-2,3-diphenylpropanoate. Alkyl 3,3-diphenylpropenoates gave mainly alkyl 2-chloro-3,3-diphenyl-propenoates. Ethyl 1-cyclohexenecarboxylate gave ethyl 1,2-dichlorocyclohexanecarboxylate. Dimethyl malonate yielded dimethyl dichloromalonate and tetramethyl 1,2-dichloro-1,1,2,2-ethanetetracarboxylate. Substituted malonates resulted in α-chloro derivatives. Methyl phenylacetates gave α-acetoxy derivatives.

The reaction of 1-octene with manganese(III) acetate in acetic anhydride/acetic acid mixtures in the presence of Cu(II) salts gives 4-decenoic acid as a major product, together with some 3-decenoic acid. The 4-decenoic acid, after esterification, is shown to consist mainly of the trans-isomer, some cis-isomer being also present. 4-Acetoxydecanoic acid, γ-hexyl-γ-butyrolactone and decanoic acid are minor side products. A reaction mechanism is proposed.

Oxidations with manganese (III) acetate can be broadly divided into two classes: 1. Direct inner- or outer-sphere one-electron oxidation of the substrate after formation of an inner- or outer-sphere substrate-Mn(III) complex. Often subsequent oxidation of an intermediate radical is product determining. Numerous examples can be found in oxidations of alcohols, amino- and thio-compounds, carboxylic acids, and certain aromatics. 2. Indirect oxidation of the substrate after formation of an intermediate adduct free radical from interaction of manganese (III) acetate and an enolizable compound and subsequent addition or substitution of this radical to the substrate. Most examples here refer to aromatic substitution and oxidative addition of enolizable compounds to unsaturated systems.

1-Hexene and 2-methyl-2-pentene were heated with manganese(III) acetate at 100 °C in two mixed solvents of glacial acetic acid and acetic anhydride and of propionic acid and propionic anhydride in a nitrogen flow. γ-Acyloxy carboxylic acids, γ-lactones and saturated and unsaturated carboxylic acids were obtained, these oxidative products being considered to be adducts of acetic and propionic acids. Additional investigations were carried out on a mutual reaction of the oxidant and the solvents and on the thermal analysis of manganese(III) acetate. The reaction was explained by a solvent-participating free-radical mechanism.

The reaction of biphenylene with manganese (III) acetate gave 2-acetoxybiphenylene, 2-formylbiphenylene, 2-(acetoxymethyl)biphenylene, and 7-oxa-10,11-benzotricyclo[4.3.2.0]undeca-2,4,10-trien-8-one. The reaction pathways are discussed.

The reaction of methylmalonic acid with mono- and disubstituted olefins in the presence of manganese(III) acetate yielded 2-carboxy-2-methyl-4-butanolides in moderate to good yields. The reactions of bromomalonic acid and chloromalonic acid with a variety of olefins gave 2-halo-4-butanolides and/or 2-buten-4-olides. The reaction of ethyl hydrogen malonate with olefins in the presence of manganese(III) acetate yielded 2-ethoxycarbonyl-2-buten-4-olides, 2-ethoxycarbonyl-2-ethenyl-4-butanolide, 2,7-dioxaspiro[4.4]nonane-1,6-diones, 2-ethoxycarbonyl-4-butanolide, and ethyl 3-butenoate. These reactions can be accounted for in terms of a free-radical mechanism involving substituted dicarboxymethyl radicals.