Exchange reactions diketones

Selectivity in formation of protective groups may also be achieved by a proper choice of reaction conditions and catalyst. Thus formation of the 3-monothioketal from 3,6-diketones is achieved by dilution of the ethane-dithiol-boron trifluoride reaction mixture with acetic acid. 3-Monocyanohydrins are obtained in good yield from 3,20-diketo-(5a)-pregnanes by diluting the exchange reaction with ethanol. Similarly, dilution of the... 

Chromium, (ri6-benzene)tricarbonyl-stereochemistry nomenclature, 1,131 Chromium complexes, 3,699-948 acetylacetone complex formation, 2,386 exchange reactions, 2,380 amidines, 2,276 bridging ligands, 2,198 chelating ligands, 2,203 anionic oxo halides, 3,944 applications, 6,1014 azo dyes, 6,41 biological effects, 3,947 carbamic acid, 2,450 paddlewheel structure, 2, 451 carboxylic acids, 2,438 trinuclear, 2, 441 carcinogenicity, 3, 947 corroles, 2, 874 crystal structures, 3, 702 cyanides, 3, 703 1,4-diaza-1,3-butadiene, 2,209 1,3-diketones... 

DioxaphosphoIens.—The condensation of a-diketones with tervalent phosphorus compounds has been extended to monothiobenzil.43 Hydrolysis of the resulting adducts (59) gave both P-O and P-S bond fission. Exchange reactions on the benzil-... 

In addition to the compounds 57, 60, and 61 listed in Tables II-IV, further l,3,2-2 -dioxaphospholanes are accessible via halogen exchange reactions 106,115, 229, 230, 232, 263, 263a, 277) (vide infra), oxidative addition of a,/S-diketones to 2 -dioxaphospholanes (32), hydrolysis of silylamino compounds with HCl to yield unsubstituted amines (121), and thermal elimination of McsSiF from the silylaminofluoro derivatives 57ah and 57ai (115,118). 

Exchange reactions with amines and thiols (X = N, S in Fig. 156) are the most studied (see below) however, interesting C-alkylations, - based on the rather unusual replacement by bis-aldehyde (402, Fig. 157) to give poly( 5-diketone)s 403, have also been performed. 

Hydrolysis (the reverse of the preparative reaction) and other exchange reactions of the metal /3-diketonates have been studied in some detail in order to probe the mechanisms of inorganic substitution reactions. As mentioned in Section 4.1, there has been intense study of the intramolecular rearrangements of M(dike)3 complexes. Decomposition of metal /1-diketonate complexes to give high-purity metals or metal oxides is of technological importance. 

Grinding of [Tc(CO)5Cl) with the potassium salts of several /1-diketonates (KL) under a layer of CCI4 induces the exchange reaction ... 

An access to unsymmetrical 1,6-diketones by conjugate addition of y-keto zincates to enones relies on successful enolization and a Sn-Zn exchange reaction of p-stannyl ketones.- ... 

Protection of 1,2-diols. These reagents are prepared from the diketones and HC(OMe)j in methanol containing a little sulfuric acid. By an acid-catalyzed exchange reaction, 2,3-dimethoxy-l,4-dioxane derivatives are formed in the reaction with 1,2-diols. Diequatorial diols are selectively protected. Actually, the protection can be performed directly by the reaction of a 1,2-diol with an a-diketone, trimethyl orthoformate, in methanol in the presence of camphorsulfonic acid. ... 

R = Ph) " have been prepared by reaction of blue ruthenium(III) chloride with the corresponding diketone under basic conditions or by ligand exchange with [Ru(acac)3]. The tris chelate complexes of (-t-)-3-acetylcamphor and (-i-)-3-trifluoroacetylcamphor [RUL3], for example, have been prepared by ligand exchange reaction with [Ru(acac)3] in ethyl benzoate at 160°C the diastereomers have been separated by tic on silica and assigned by H NMR studies. For tris complexes of... 

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