Nickel acetylacetonate derivatives

Nickel acetylacetonate, Ni(acac)2, in the presence of a styrene derivative promotes coupling of primary alkyl iodides with organozinc reagents. The added styrene serves to stabilize the active catalytic species, and of the derivatives examined, m-trifluoromethylstyrene was the best.274... 

Ligand-free catalysts have been prepared from the following types of nickel(II) compounds nickel salts of long-chain aliphatic or aromatic carboxylic acids (10, 11) or of sulfonic acids (11), nickel enolates of /3-diketones (11) [e.g., nickel acetylacetonate (4, 12)] or their imino derivatives (11, 13), nickel phenolates (11), dithiocarbamates (14), and mer-captides (15). 

A full account has appeared of the study of absolute configurations of vicinal diols and amino-alcohols by c.d. measurements in solutions containing nickel acetylacetonate [Ni(acac)2] or the n.m.r. shift reagent [Pr(dpm)3]. Examples of steroidal derivatives examined include 2,3-, 3,4-, 5,6-, 16,17-, 17a,20j8-, and side-chain diols. 

The asymmetric conjugate addition of diethylzinc with chalcone was also catalyzed by nickel and cobalt complex (Eq. (12.31)) [71]. A catalytic process was achieved by using a combination of 17 mol% of an aminoalcohol 34 and nickel acetylacetonate in the reaction of diethylzinc and chalcone to provide the product in 90% ee [72, 73]. Proline-derived chiral diamine 35 was also effective, giving 82% ee [74]. Camphor-derived tridentate aminoalcohol 36 also catalyzes the conjugate addition reaction of diethylzinc in the presence of nickel acetylacetonate to afford the product in 83% ee [75]. Similarly, the ligand 37-cobalt acetylacetonate complex catalyzes the reaction to afford the product in 83% ee [76]. 

Lithium477 and potassium478 enolates of P-dicarbonyl compounds are aminated by azodicarboxylic esters in good to excellent yields. Diethyl malonate, ethyl acetoacetate, /V,/V-diethyI acetoacetamide, and acetylacetone have also been aminated with diethyl azodicarboxylate under nickel acetylacetonate catalysis,479 and nickel salicylideneimine complexes catalyze the analogous amination of acetylacetone and its 2-methyl derivative.480... 

The interpretation of the experimental a constants for the fluoroalkyl and nitroxide radicals is complicated because the stereochemistry at the radical center is not well defined. This complication does not exist for radicals derived from aromatic compounds. Consequently, several research groups have investigated aromatic radicals to characterize the factors governing spin delocalization to /3-fluorine atoms. One aspect of this work concerns the epr spectra of nitrobenzene anion radicals. Another concerns the contact chemical shifts of paramagnetic transition metal complexes. The latter approach was initiated by Eaton, Josey, and Sheppard who examined stable bis(phenylaminotroponiminato)-nickel(II) complexes (55a). More recently, we have examined the contact chemical shifts in the nmr spectra of nickel acetylacetonate complexes of aniline derivatives (556). 

The complex Ni(7r-l,5-CgHi2)2, presumably a tetrahedral complex of Ni(0), has been obtained as air-sensitive, yellow crystals by ligand displacement from Ni(cyclododecatriene), or by reducing nickel acetylacetonate with alkyl aluminums in the presence of the diene 133). Derivatives such as CgHi2Ni(acac) and CsHi2Ni(PPh3)2 have also been mentioned 134). This work is summarized elsewhere 124). 

The kind of the complexing group used in the first step of the synthesis also has a pronounced influence on the resulting metal particle diameters. The mean particle diameter in Ni 15 Si02 decreases from 22.9 nm to 2.6 nm (same reaction conditions during step 2 and 3), if the acetylacetone derivative [CH3(0)C]2CH-(CH2)3Si(OR)3 is used for the complexation of the nickel ions during sol-gel processing instead of the ethylene diamine derivative DIAMO. 

The reaction of the nickel(II) perchlorate complex (89) with acetone and related ketones yields simple hydrazone complexes rather than macrocyclic complexes resulting from a Curtis-type reaction. Acetylacetone also fails to bridge the bis(hydrazine) and instead yields a pyrazole derivative (Scheme 37).197 198 In contrast to this result, 1,4-dihydrazinophthalazine undergoes a template reaction with 2,2-dimethoxypropane, a source of acetone, in the presence of nickel(II) fluoroborate and a trace of fluoroboric acid (Scheme 38).199... 

Butadiene and secondary amines, with a catalyst formed from nickel(II) acetylacetonate and triethylaluminum in the presence of chiral phosphonite ligands derived from menthol, 1,2 5.6-di-O-isopropylideneglucose or cholesterol, give linear and branched telomers along with simple addition products and cyclic dimers6. The linear telomers are the major products. An optical yield of 37 % was obtained for the branched morpholine telomer 2. which was obtained in 30 % yield when bis(menthoxy)(2-methylpropyl)phosphane was employed. 

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