Chloroperbenzoic acid, meta

Epoxidation of olefins with meta-chloroperbenzoic acid, (MCPBA) remains to this day among the most widely used methods for research-scale applications [16], Discovered by Nikolai Prilezahev in 1909 [17], it became popular only decades later, mostly through the works of Daniel Swern in the 1940s [18]. Despite its simplicity, and not unlike most epoxidation methods in use today, it suffers from undesired epoxide opening caused by the slight acidity of the reaction milieu. Although acid-catalyzed side reactions can sometimes be minimized by use of buffered systems... 

It cannot be mled out that the reactions of SENAs with meta-chloroperbenzoic acid (184) involve the cationic attack on the a-C-atom of the nitronate (Scheme 3.97). 

Oxidation of 2,3-dihydrobenzodiazepines by various oxidants (H202, Se02, peracids, etc.) normally gives resinous reaction products which cannot be easily identified. However, described in [107] is the oxidation of 7V-bezoyl derivatives of benzodiazepines 97 by meta-chloroperbenzoic acid in the presence of sodium bicarbonate and triethylbenzyl ammonium chloride (used as an interphase catalyst) which yields compounds 98 (Scheme 4.32). 

The conversion of vinylsilanes into epoxysilanes was first published by Stork and Colvin74 in 1971. They added meta-chloroperbenzoic acid (87) to l-TMS-3-hydroxy-... 

In a Michael-type addition 192 is converted by treatment with mesityl oxide (207) or methyl acrylate (209) under equal conditions (TiCl4) to 1 -phenyl-3,3-di-methyl-l,5-hexanedione (208) and methyl 7-benzoyl-butyrate (210)14i respectively. 193 reacts with meta-chloroperbenzoic acid (87) to yield 2-trimethylsiloxy-cyclohexanone (2ii)142 ... 

Baeyer-Villiger oxidation of ketone 7, an oxidation with meta-chloroperbenzoic acid, gave a very good yield of a mixture of formates 8 and 9... 

Abbreviations AD, asymmetric dihydroxylation BPY, 2,2 -bipyridine DMTACN, 1,4-dimethyl-l,4,7-triazacyclonane EBHP, ethylbenzene hydroperoxide ee, enantiomeric excess HAP, hydroxyapatite LDH, layered double hydroxide or hydrotalcite-type structure mCPBA, meta-chloroperbenzoic acid MTO, methyltrioxorhenium NMO, A-methylmorpholine-A-oxide OMS, octahedral molecular sieve Pc, phthalocyanine phen, 1,10-phenantroline PILC, pillared clay PBI, polybenzimidazole PI, polyimide Por, porphyrin PPNO, 4-phenylpyridine-A-oxide PS, polystyrene PVP, polyvinylpyridine SLPC, supported liquid-phase catalysis f-BuOOH, tertiary butylhydroperoxide TEMPO, 2,2,6,6-tetramethyl-l-piperdinyloxy TEOS, tetraethoxysilane TS-1, titanium silicalite 1 XPS, X-ray photoelectron spectroscopy. 

A one-sided binding of the complex to the support resulted in further improvements (92). This requires synthesis of nonsymmetric salen-type ligands, which is complicated by the tendency of such ligands to equilibrate to give mixtures containing symmetric Schiff bases. Excellent results were obtained with monomer 7d, diluted in a methacrylate polymer, by using a combination of meta-chloroperbenzoic acid (mCPBA) and A-methyl-morpholine-A-oxide (NMO) as the oxidants ... 

Another one-step addition reaction to C=C double bonds that forms three-membered rings is the epoxidation of alkenes with percarboxylic acids (Figure 3.19). Most often, meta-chloroperbenzoic acid (MCPBA) is used for epoxidations. Magnesium monoperoxyphthalate (MMPP) has become an alternative. Imidopercarboxylic acids are used to epoxidize olefins as well. Their use (for this purpose) is mandatory when the substrate contains a ketonic C=0 double bond in addition to the C=C double bond. In compounds of this type, percarboxylic acids preferentially cause a Baeyer-Villiger oxidation of the ketone (see Section 14.4.2), whereas imidopercarboxylic acids selectively effect epoxidations (for an example see Figure 14.35). 

Fig. 6.17. SN reactions with H202 at the carboxyl carbon. Syntheses of meta-chloroperbenzoic acid (A), magnesium monoperoxophthalate hexahydrate (B), and dibenzoyl peroxide (C).

Fig. 11.32. Regioselective Baeyer-Villiger rearrangement of an asymmetric ketone with MCPBA (meta-chloroperbenzoic acid). The aryl group is [1,2]-shifted in all cases and irrespective of whether the acetophenone is electron rich or electron poor.

Baeyer-Villiger reactions are among the most useful of all rearrangement reactions, and the most common reagent is m-CPBA (meta-chloroperbenzoic acid) because it is commercially available. 

In the second step meta-chloroperbenzoic acid (MCPBA) epoxidizes the resulting bis-acetal from the y0-face. The weak 0-0 bond of MCPBA undergoes attack by electron rich substrates like alkenes. This reaction is syn stereospecific and believed to take place via transition state 48. ... 

A racemic mixture of the selenurane oxide 20 was prepared by oxidation of the parent selenurane 21 with meta-chloroperbenzoic acid <2001PS253, 2004CH1598>. The parent selenurane 21 can be regenerated by treatment with HCl <2002HAC437>. 

A number of pyridazines were selected for further deriva-tization based on their herbicidal activity. Pyridazines containing methoxy, substituted-amino, chloro, and hydrogen in the 3-position were selectively reduced using platinum oxide in tri-fluoroacetic acid to yield the corresponding 6-cyclohexyl derivatives (2.) Selected analogs were also oxidized in the 1-and/or 2-positions using meta-chloroperbenzoic acid (8) and were quater-nized with methyl iodide in refluxing acetonitrile (9) to... 

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