Corey oxidation

COREY Oxidizing reagents for alcohols 76 COREY Enantnseleetivs borane reduction 77 COREY Hi COREY -1 COREY-WINTERAlkenesynthesis 80 CORNEORTH Reanangement 81 Crafts 131... 

COREY Oxidizing reagents for alcohols 76 COREY Enantneelective borane reduction 77... 

N-Chlorosuccinimide dimethyl sulfide triethylamine Corey oxidation Ketones from sec. alcohols... 

Copyrolysis 31,791 Corey oxidation 28,201 Comforth oxazole rearrangement 31, 318 Corrins... 

The conversion of primary alcohols and aldehydes into carboxylic acids is generally possible with all strong oxidants. Silver(II) oxide in THF/water is particularly useful as a neutral oxidant (E.J. Corey, 1968 A). The direct conversion of primary alcohols into carboxylic esters is achieved with MnOj in the presence of hydrogen cyanide and alcohols (E.J. Corey, 1968 A,D). The remarkably smooth oxidation of ethers to esters by ruthenium tetroxide has been employed quite often (D.G. Lee, 1973). Dibutyl ether affords butyl butanoate, and tetra-hydrofuran yields butyrolactone almost quantitatively. More complex educts also give acceptable yields (M.E. Wolff, 1963). 

Regioselectivity of C—C double bond formation can also be achieved in the reductiv or oxidative elimination of two functional groups from adjacent carbon atoms. Well estab llshed methods in synthesis include the reductive cleavage of cyclic thionocarbonates derivec from glycols (E.J. Corey, 1968 C W. Hartmann, 1972), the reduction of epoxides with Zn/Nal or of dihalides with metals, organometallic compounds, or Nal/acetone (seep.lS6f), and the oxidative decarboxylation of 1,2-dicarboxylic acids (C.A. Grob, 1958 S. Masamune, 1966 R.A. Sheldon, 1972) or their r-butyl peresters (E.N. Cain, 1969). 

Six protective groups for alcohols, which may be removed successively and selectively, have been listed by E.J. Corey (1972B). A hypothetical hexahydroxy compound with hydroxy groups 1 to 6 protected as (1) acetate, (2) 2,2,2-trichloroethyl carbonate, (3) benzyl ether, (4) dimethyl-t-butylsilyl ether, (5) 2-tetrahydropyranyl ether, and (6) methyl ether may be unmasked in that order by the reagents (1) KjCO, or NH, in CHjOH, (2) Zn in CHjOH or AcOH, (3) over Pd, (4) F", (5) wet acetic acid, and (6) BBrj. The groups may also be exposed to the same reagents in the order A 5, 2, 1, 3, 6. The (4-methoxyphenyl)methyl group (=MPM = p-methoxybenzyl, PMB) can be oxidized to a benzaldehyde derivative and thereby be removed at room temperature under neutral conditions (Y- Oikawa, 1982 R. Johansson, 1984 T. Fukuyama, 1985). 

This method for the preparation of cyclobutanone via oxaspiropentane is an adaptation of that described by Salaiin and Conia. The previously known large-scale preparations of cyclobutanone consist of the reaction of the hazardous diazomethane with ketene, the oxidative degradation or the ozonization in presence of pjrridine of methylenecyclobutane prepared from pentaerythritol, or the recently reported dithiane method of Corey and Seebach, which has the disadvantage of producing an aqueous solution of the highly water-soluble cyclobutanone. A procedure involving the solvolytic cyclization of 3-butyn-l-yl trifluoro-methanesulfonate is described in Org. Syn., 54, 84 (1974). 

In Corey and Chaykovsky s initial investigation, a cyclic ylide 79 was observed from the reaction of ethyl cinnamate with ylide 1 in addition to 32% of cyclopropane 53. In a similar fashion, an intermolecular cycloaddition between 2-acyl-3,3-bis(methylthio)acrylnitrile 80 and 1 furnished 1-methylthiabenzene 1-oxide 81. Similar cases are found in transformations of ynone 82 to 1-arylthiabenzene 1-oxide 83 and N-cyanoimidate 84 to adduct ylide 85, which was subsequently transformed to 1-methyl-lX -4-thiazin-l-oxide 86. ... 

The Baeyer-Villiger oxidation is a synthetically very useful reaction it is for example often used in the synthesis of natural products. The Corey lactone 11 is a key intermediate in the total synthesis of the physiologically active prostaglandins. It can be prepared from the lactone 10, which in turn is obtained from the bicyclic ketone 9 by reaction with m-chloroperbenzoic acid (MCPBA) " ... 

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