Stille reaction involving acid chlorides

In another nonelectrolytic process, arylacetic acids are converted to vi c-diaryl compounds 2A1CR2COOH —> ArCR2CR2Ar by treatment with sodium persulfate (Na2S20g) and a catalytic amount of AgNOs." Both of these reactions involve dimerization of free radicals. In still another process, electron-deficient aromatic acyl chlorides are dimerized to biaryls (2 ArCOCl —> ArAr) by treatment with a disilane RsSiSiRs and a palladium catalyst." " ... 

Diketones are converted into pyranones on treatment with malonyl dichloride, involving both C- and O-acylation (63JCS4483). The reaction between benzoylacetone and the acid chloride gives only one pyranone in accordance with a preferred direction of enolization consequent upon the unsymmetrical nature of the diketone a 5-acetyl-6-phenylpyranone results rather than the 5-benzoyl-6-methyl isomer. There is still some uncertainty as to whether the product is the 4-hydroxypyran-2-one (409) or the tautomer, but the former is considered to be the more likely. There is yet further controversy, since... 

The Stille coupling is a cross-coupling reaction that involves an organotin reagent as one reactant. In the presence of appropriate palladium catalysts, alkenyl and aryl tin reactants can be coupled with alkenyl triflates, iodides, and bromides, as well as allylic chlorides and acid chlorides. 

As compared to the direct esterifications, the amidations had a lower enthalpy of activation (ca. 79 vs ca. 102 kcal/ mol) however, the amidations were significantly endothermic (33kcal/mol) [39]. It is recalled herein that the esterifications are thermoneutral [35]. As far as such amidation reactions are concerned, it is the fact that the MW-assisted reaction of phosphinic acids and amines is of limited use and the traditional method involving the reaction of phosphinic chlorides with amines still remains the method of choice (Scheme 5). During the preparation of l-amino-3-phospholene oxides (21) by this method, an interesting side reaction was also found to take place yielding a bis(phosphinoyl) amine (22) (Scheme 6) [40]. However, using appropriate molar ratios and addition techniques, both e formation of the amino-3-phospholene oxides (21) and that of the bis(products) (22) could be optimized [40]. 

Alkanes and Strong Solid Acids. Since the early reports by Nenizetscu and Dragan67 on alkane isomerization on wet aluminum chloride in 1933, all mechanistic studies have led to a general agreement on the carbenium-ion-type nature of the reaction intermediates involved in acid-catalyzed hydrocarbon conversions. In contrast with this statement, the nature of the initial step is still under discussion and a variety of suggestions can be found in the literature among which direct protolysis of C—H and C—C bonds, protonation of alkenes present as traces, and oxidative activation are the most often quoted.54,55... 

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