Addition of carboxylic acids and

This novel catalytic reaction formally corresponds to an initial regioselective [2+2] head-to-head cyclodimerization of the propargyl alcohol with addition of carboxylic acid and elimination of water. Catalytic alkenylidenecyclobutene formation is general for a variety of propargyl alcohols and carboxylic acids and can also be applied to phenol derivatives. 

The above results show that the ruthenium-catalyzed activation of alkynes towards nucleophiles has first led to classical electrophilic activation, leading to Markovnikov additions as observed for addition of carboxylic acids and the synthesis of enol esters. In 1986, the regioselective anfi-Markovnikov addition of in-situ-generated... 

Y. Addition of carboxylic acids and alcohols to olefins and acetylenes... 

Thallium(m) acetate effects a one-step synthesis of aliphatic a-acyloxy-carboxylic acids (Scheme 28) the transition state (92) is proposed. a-Aminoesters are readily oxidized to the corresponding a-diazoesters by isoamyl nitrite in the presence of acetic acid. A review has been published on the radical addition of carboxylic acids and derivatives to unsaturated linkages. ... 

Recently, other groups have also examined the chemistry of trifluoromethylated alkynes, such as 1,3-dipolar cyclo-addition, the reaction of Cp3-containing titanacycle with various electrophiles, Ru3(CO)/PPh3-catalyzed addition of carboxylic acids, and Ru3(CO)i2/2-DPPBN-catalyzed... 

Interest in synthetic naphthenic acid has grown as the supply of natural product has fluctuated. Oxidation of naphthene-based hydrocarbons has been studied extensively (35—37), but no commercially viable processes are known. Extensive purification schemes must be employed to maximize naphthene content in the feedstock and remove hydroxy acids and nonacidic by-products from the oxidation product. Free-radical addition of carboxylic acids to olefins (38,39) and addition of unsaturated fatty acids to cycloparaffins (40) have also been studied but have not been commercialized. 

It is appropriate to add here some comments on diazotization in anhydrous carboxylic acids. They may be relevant for the diazotization of heteroaromatic amines carried out in acetic acid/propionic acid mixtures (Sec. 2.2). Extensive studies by Casado et al. (1983, 1984) showed that in nitrosation of secondary amines the nitrosyl ion, nitrosyl acetate, and dinitrogen trioxide are formed, and all three may act as nitrosating agents. The results do not, however, account for the considerable improvement that is claimed in the patent literature (Weaver and Shuttleworth, 1982) to result from the addition of carboxylic acids in the diazotization of heteroaromatic amines. 

When a carbonyl group is bonded to a substituent group that can potentially depart as a Lewis base, addition of a nucleophile to the carbonyl carbon leads to elimination and the regeneration of a carbon-oxygen double bond. Esters undergo hydrolysis with alkali hydroxides to form alkali metal salts of carboxylic acids and alcohols. Amides undergo hydrolysis with mineral acids to form carboxylic acids and amine salts. Carbamates undergo alkaline hydrolysis to form amines, carbon dioxide, and alcohols. 

Carboxylic esters are produced by the addition of carboxylic acids to alkenes, a reaction that is usually acid catalyzed (by proton or Lewis acids ) and similar in mechanism to 15-5. Since Markovnikov s rule is followed, hard-to-get esters of... 

For a review of the addition of thio acids, see Janssen, M.J. in Patai The Chemistry of Carboxylic Acids and Esters Wiley NY, 1969, p. 720. 

Addition of carboxylic acids to alkynes Acylation of aldehydes or ketones Bisdecarboxylation of malonic acids Oxidation of arylmethanes with CrOs and AC2O... 

On the other hand, following the same sequences from the differently protected serine-derived nitrone 168, through the formation of hydroxylamines 169, C2 epimers of carboxylic acid and aldehydes are obtained, i.e., (2S,3R)-170 and (2S,3R)-171. Moreover, the syn adducts 164 were exclusively obtained in the addition of Grignard reagents to the nitrone 163, whereas the same reactions on nitrone 168 occurred with a partial loss of diastereoselectivity [80]. Q, j6-Diamino acids (2R,3S)- and (2R,3R)-167 can also be prepared from the a-amino hydroxylamines 164 and 169 by reduction, deprotection and oxidation steps. The diastereoselective addition of acetylide anion to N,N-dibenzyl L-serine phenyhmine has been also described [81]. 

Choi and Sakakura et al. reported that iron(III) triflate, in situ formed from FeCls and triflic acid, efficiently catalyzes the intermolecular addition of carboxylic acids to various alkenes to yield carboxylic esters. The reaction is applicable to the synthesis of unstable esters, such as acrylates (Scheme 40) [50]. 

Henriksen et al. 1991). A comparable phenomenon is the enhanced dechlorination of tetrachloroethene in anaerobic microcosms by the addition of carboxylic acids including lactate, propionate, butyrate, and crotonate (Gibson and Sewell 1992). 

Barium oxide and sodium hydride are more potent catalysts than silver oxide. With barium oxide catalysis, reactions occur more rapidly but O-acetyl migration is promoted. With sodiun hydride, even sterically hindered groups may be quantitatively alkylated but unwanted C-alkylation Instead of, or in addition to, 0-alkylatlon is a possibility. Sodium hydroxide is a suitable catalyst for the alkylation of carboxylic acids and alcohols [497J. 

Acetaldehyde is the product of the Wacker process. At the end of the fifties oxidation of ethene to ethanal replaced the addition of water to acetylene, because the acetylene/coal-based chemistry became obsolete, and the ethene/petrochemistry entered the commercial organic chemicals scene. The acetylene route involved one of the oldest organometallics-mediated catalytic routes started up in the 1920s the catalyst system comprised mercury in sulfuric acid. Coordination of acetylene to mercury(II) activates it toward nucleophilic attack of water, but the reaction is slow and large reactor volumes of this toxic catalyst were needed. An equally slow related catalytic process, the zinc catalysed addition of carboxylic acids to acetylene, is still in use in paint manufacture. 

The addition of carboxylic acids to bicyclo[2.2.1]hepta-2,5-diene has been described by several authors the method described here is a modification of these procedures. Nortricyclanol has been prepared by the hydration of bicyclo[2.2.1]hepta-2,5-diene and the solvolysis of nortricyclyl and bicyclo[2.2.1]hept-2-en-5-yl halides, as well as by the saponification and... 

Reduction of the carboxylic acid group passes through the intermediate aldehyde. For a number of examples in the heterocyclic series, the aldehyde becomes a major product because it is trapped as the hydrated vfc.-diol form. Examples include imidazole-2-caiboxylic acid [139], thiazole-2-carboxylic acid [140] and pyridine-4-carboxylic acid [141] reduced in dilute aqueous acid solution. Reduction of imidazole-4-carboxylic acid proceeds to the primary alcohol stage, the aldehyde intermediate is not isolated. Addition of boric acid and sodium sulphite to the electrolyte may allow the aldehyde intermediate to be trapped as a non-reducible complex, Salicylaldehyde had been obtained on a pilot plant scale in this way by... 

For this selective addition, the best catalyst precursors were Ru(methallyl)2(dppe) 1 and Ru(methallyl)2(dppb) 2. The choice of the appropriate complex depended on the steric demand of both the alkyne and the carboxylic acid. A large variety of carboxylic acids and alkynes have been used, including N-protected amino acids, a-hydroxy acids, and functionalized alkynes such as enynes, diynes and propargylic ethers [21-23] (Scheme 10.4). The addition took place under mild conditions and carboxylic adds of... 

In the 1990s, the groups of Hiemstra and Larock independently discovered that Pd(OAc)2 in DMSO serves as an effective catalyst for direct dioxygen-coupled catalytic turnover, and this catalyst system was applied widely to oxidative heterocyclization reactions. Examples include the addition of carboxylic acid, phenol, alcohol, formamide, and sulfonamide nucleophiles to pendant olefins (Eq. 26) [146-149]. 

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