Manganic acid ester

Another reaction in which the cleavage of a carbon-hydrogen bond is important is the bromination of ketones. In the bromination of ethyl acetoacetate and 2-carboethoxycyclopentanone, it was shown that multivalent cations are catalysts. In the latter reaction, cupric, nickelous, lanthanum, zinc, plumbous, manganous, cadmium, magnesium, and calcium ions were effective (45). One can interpret the effect of the metal ion in terms of its catalysis of the proton transfer from the ester to a base, whether the reaction is carried out in dilute hydrochloric acid solution (acid-catalyzed bromination) or in acetate buffer (base-catalyzed bromination). 

The preparation of ketones by dehydrogenation of secondary alcohols over zinc and copper catalysts and the decarboxylation condensation of acids over manganous oxide or thoria have been adequately covered by standard reference books on catalysis. However, the more complete but equally serviceable catalytic syntheses involving either an aldol or a Tischenko ester type of condensation have been virtually ignored. 

A wide variety of substituted y-butyrolactones can be prepared directly from olefins and aliphatic carboxylic acids by treatment with manganic acetate. This procedure is illustrated in the preparation of 7-( -OCTYL)-y-BUTYROLACTONE. Methods for the synthesis of chiral molecules are presently the target of intensive investigation. One such general method developed recently is the employment of certain chiral solvents as auxiliary agents in asymmetric synthesis. The preparation of (S.SM+H, 4-BIS(DIMETHYLAMINO)-2,3-DIMETHOXY-BUTANE FROM TARTARIC ACID DIETHYL ESTER provides a detailed procedure for the production of this useful chiral media an example of its utility in the synthesis of (+)-(/ )-l-PHENYL-l-PEN-TANOL from benzaldehyde and butyllithium is provided. 

Calcium bromide Citric acid Ferric oxide Hydrated lime Manganic oxide Natural fatty acids Potassium bromide Potassium chloride Potassium sulphate Phosphate esters Silicates (inorganic)... 

Addition of the permanganate ion to alkenes and alkynes produces a cyclic manganate ester which cleaves to give carboxylic acids. This method used for the determination of the position of an olefin in an unsaturated alkyl chain requires vigorous conditions when alkynes are to be cleaved. 

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