Ketones enolesters

Die Enolester von 3-Oxo-aldehyden (z. B. I) werden oft mit guten Ausbeuten unter Erhalt von Carbonyl-Gruppen in die entsprechenden a -Methyl-ketone iiber fiihrt. So gelingt es, auf einfache Weise l-Oxo-2-methyl-tetraline herzustellen2 ... 

Markownikoff addition. 2-Methylpent-l-ene allowed to react with tertAmiyl hydroperoxide and mercuric acetate with initial cooling and shaking, after 2 hrs. the volatiles removed by distillation in vacuo, and the residue digested repeatedly with coned, aq. NaCl -> l-diloromercuri-2-tert-butylperoxy-2-methylpentane. Y 19%. F. e., also hydroperoxymercuration with H2 2 s. E. Schmitz, A. Riedie, and O. Brede, J. pr. 312, 30 (1970) a-alkoxyketones from enolesters s. ibid. 312, 43 peroxy- and methoxy-mercuration of a,i -unsatd. ketones and esters s. A. J. Bloodworth and R. J. Bunce, Soc. (C) 1971, 1453. 

Enollactones from ketocarboxylic acids s. 19, 328 also enolesters from ketones, and dienone-phenol rearrangement s. J. Org. Chem. 31, 324 (1966)... 

Ketones from enolesters with retention of ketal groups... 

Oxalic ester synthesis—Enolesters from ketones. 6 g. dl-zl5,14-3.Ethylenedioxy-lly ,18-oxido-16-oxo-18-tetrahydropyranyloxyandrostadiene and dimethyl oxalate in benzene added dropwise to NaH in oil (Metal Hydrides, Inc., Beverly, Mass., USA) and benzene, stirred 48 hrs. at 30° in a slow Ng-stream, the crude product dissolved in benzene, and allowed to stand at room temp, overnight with acetic anhydride and pyridine 6.61 g. methyl dl-J5,14,17(20)-3-ethylene-dioxy-1 ly, 18- oxid o-16- oxo-18- tetrahydropyranyloxy - 20 - acetoxypregnatrien-21-ate, 6 g. suspended in an ice-cold 10 1 mixture of morpholine and water, stirred 3-4 hrs. until a clear soln. results, allowed to stand 24 hrs. at ca. 10°, evaporated almost to dryness at 35-40°/0.05 mm., a mixture of benzene and ether then pyridine added, ice-cooled, acetic anhydride added, and allowed to stand 24 hrs. at room temp. 5.55 g. dl-j5,14,17(20)-3-ethylenedioxy-ll, 18-oxido-16-oxo-18-tetrahydropyranyloxy-20-acetoxypregnatrien-21-ic acid morpholide.—Morpholine is preferred to other sec. amines because of its good solvent properties (cf. Synth. Meth. lA, 87). Use of anhydrous amines caused decomposition. K. Heus-ler, P. Wieland, and A. Wettstein, Helv. A2, 1586 (1959). 

Synthesis of ketones, enolesters, and a-hydroxyketones from a,j -ethyleneketones... 

Enolesters from ketones with isopropenyl acetate... 

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