Boron complexes acetylacetone

The boron difluoride coordination complex is decomposed by heating under reflux with an aqueous solution of 2 mols of sodium acetate per mol of anhydride, whereupon the p diketone (acetylacetone) is liberated. 

These NMR experiments provided great insight into the catalytic reaction. Whereas the catalytic reaction requires a high reachon temperature of 100 °C, aU three transformations in Scheme 3.5 proceed at 25 °C. In the same paper [16], Hayashi answered the question of why the catalytic reaction does not take place at the lower temperature. An outline of the reason is illustrated in Scheme 3.6. In the catalytic reaction, Rh(acac)(BINAP) is involved as a significant intermediate, because Rh(acac)(C2H4)2 is used as the rhodium precursor. It was confirmed that the hydroxo-rhodium complex is immediately converted into Rh(acac) (BINAP) by the reaction with 1 equiv. acetylacetone at 25 °C, in which the transmetallation from boron to rhodium is very slow at the same temperature. Thus, the acetylacetonato Hgand inhibits the catalytic reaction (Scheme 3.6, path a). 

Treatment of chromium (III) acetylacetonate with acetic anhydride and boron trifluoride etherate yielded a complex mixture of acetylated chelates but very little starting material. Fractional crystallization and chromatographic purification of this mixture afforded the triacetylated chromium chelate (XVI), which was also prepared from pure triacetylmethane by a nonaqueous chelation reaction (8, 11). The enolic triacetylmethane was prepared by treating acetylacetone with ketene. The sharp contrast between the chemical properties of the coordinated and uncoordinated ligand is illustrated by the fact that chromium acetylacetonate does not react with ketene. 

The photostadDility of boron-containing orgamic complexes has been discussed, amd a study maule of the luminescent properties of p-diketonates of disubstituted boron amd of bis-p-diketonatoboron. A novel photochemical alkyl migration from B to C in the dialkyIboryl acetylacetonate complexes (1) ( R-cyclohexyl, Bu, isopinocaunpheyl, R -H R-cyclohexyl, Bu, R -Me ) has appeared. Crossover experiments show that the alkyl migration is essentially intraunolecular Silicon... 

Trichloro(tripyridine)chromium(III), synthesis 36 Tris(3-bromoacetylacetonato)chromium(III), synthesis 37 Cyclopentadienyl tricarbonyl hydrides of chromium, molybdenum, and tungsten, synthesis 38 Trichloro(tripyridine)molybdenum(III), synthesis 39 Potassium octacyanotungstate(IV) 2-hydrate, synthesis 40 Chlorine(CP )-labeled thionyl chloride, silicon tetrachloride, boron chloride, germanium (IV) chloride and phosphorus(III) chloride, synthesis 44 Unipositive halogen complexes, synthesis 46 Monopyridineiodine(I) chloride, synthesis 47 Manganese(III) acetylacetonate, synthesis 49 Triiron dodecacarbonyl, synthesis 52... 

The interaction between acetone and acetic anhydride yields acetylacetone in the presence of boron trifluoride which acts as an acylation catalyst and acetic acid is obtained as a by product. Acetylacetone is precipitated as its corresponding copper-complex by the addition of cupric acetate solution. Subsequently, acetylacetone is regenerated by treatment with diluted sulphuric acid and extracted successively with solvent ether. 

Condensation of 15,15 -didehydro-8 -apo-p-caroten-8 -al (52) and of 8,8 -diapocarotene-8,8 -dial (54) with butylamine in the presence of triisobutyl borate gives the Schiff bases 53 and 55, respectively. These react with the boron oxide complex of acetylacetone to give the polyene P-diketones 56 and 57. 

A 8chiff-base condensation reaction apparently results from treating the rhenium metalla-acetylacetone complex (7) with primary aromatic amines (Scheme 1). The tetracarbonylrhenium /3-diketone molecule (7) reacts with boron trihalides to give compounds (9). ... 

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