Carboxylic acids, addition compounds with

The second fundamental reaction of carbonyl compounds, nucleophilic acyl substitution, is related to the nucleophilic addition reaction just discussed but occurs only with carboxylic acid derivatives rather than with aldehydes and ketones. When the carbonyl group of a carboxylic acid derivative reacts with a nucleophile, addition occurs in the usual way, but the initially formed tetra-... 

The reactivity of oxiranes with lithium enoiates and related compounds has been widely explored and reviewed . Dianions derived from carboxylic acids react readily with oxiranes, but the reaction can be slowed by steric hindrance . The reaction of oxiranes with dianions of acetoacetates is greatly accelerated by the addition of BF3 Et20 " . Oxiranes react readily with lithium salts derived from nitriles , malonates and analogues , lithiated oxazolines and lithio enamines . 

An early effort to generate a 3-lithiated propionic acid derivative and react it with (external) electrophiles was reported in 1978 [42]. Since simple 3-lithioesters failed to undergo the required reaction, the alkyl carboxylate portion was protected by preceding conversion to the carboxylate anion. Treatment of lithium 3-bromo-propionate with lithium naphthalide generated the desired dilithiated propionic acid, which gave moderate yields of y-hydroxy acid addition products with carbonyl compounds, Eq. (45). 

However, the products may also be trifluoroacetates of the hydroxy compounds. Trifluoroacetates are favored with hydroxy compounds such as nonpolar alcohols, which are better nucleophiles than the more acidic alcohols containing polar groups such as trifluoromethyl, or phenols whose acidity is higher than that of nonpolar alcohols by as much as six or seven orders of magnitude. In addition, formation of trifluoroacetates is enhanced by addition of carbon tetrachloride, trifluoroacetic acid, or both. The presence of trifluoracetic acid may affect the reaction equilibrium between the trifluoroacetate of the hydroxy compound and the carboxylic acid by reacting with the byproduct of the reaction, carboxylic acid, and thus increase the formation of the trifluoroacetate (Guldberg-Waage s law). 

Addition reactions. a,0-Unsaturated carbonyl compounds 1 and 3 undergo exclusive 1,4-addition reactions with organolithium (and organomagnesium) compounds owing to steric hindrance of the carbonyl group. The adducts 2 and 4 are converted into carboxylic acids by cleavage with potassium t-butoxide and H2O in the case of 2 see potassium r-hutoxidc, this volume) and by treatment with ethanolic... 

Pure boron trifluoride is marketed as a compressed gas. It is utilized mainly in the organic industry as a Friedel-Crafts catalyst (Lewis acid) in the form of its complexes or addition compounds with, for example, ether, alcohols, carboxylic acids etc. or as a pure substance. 

They are often blended into compounds that are developed for injection molding applications. Where such an additive is absent, molded components tend to stick to mold surfaces. To prevent this, mold surfaces must be treated between every cycle, or they can be coated with a range of semipermanent mold release treatments. Inclusion of an internal release agent prevents mold surface build-up, surface charring, and simplifies production. Internal mold release agents may include hydrocarbons, alcohols, carboxylic acids, halogenated compounds, ketones, carboxylic acid esters, amides, metal salts, and silicone compounds. 

Tandem reactions have emerged as promising procedures for the synthesis of highly functionalised compounds in a single step. Horner-Wadsworth-Emmons reactions have been coupled with 1,4-Michael additions to prepare 6-substituted a,p-unsaturated carboxylic acids derivatives, and with Diels-Alder reactions, which utilised sugar-derived phosphonate (176) to prepare enantiomerically pure bicyclo[4.3.0]nonanes. ... 

Reduction of HAS activity in applications in flame and weather resistant polymers and coatings containing halogenated FR is solved by means of HAS having reduced basicity (Sect. 3.3.2). The danger of antagonism in blends HAS/FR is reduced by addition of hydrotalcite [270]. terf-HAS 34 may be used for stabilization of PVC in combination with the conventional HS (salts of carboxylic acids, organotin compounds) [271]. 

With certain reactants isocyanides undergo three-component condensation and with others four-component condensation.32 1 Three-component addition occurs when isocyanides react with the combinations carboxylic acid-carbonyl compound, hydrogen, azide-carbonyl compound, tropylium salt-water, or two molecules of hydrogen thiocyanate. 

R,2S)-Ephedrine has found most application, e.g., as a catalyst in photochemical proton transfer reactions (Section D.2.1.). and as its lithium salt in enantioselective deprotonations (Section D.2.1.). The amino function readily forms chiral amides with carboxylic acids and enamines with carbonyl compounds these reagents perform stereoselective carbanionic reactions, such as Michael additions (Sections D.1.5.2.1. and D. 1.5.2.4.), and alkylations (Section D.1.1.1.3.1.). They have also been used to obtain chiral alkenes for [1 +2] cycloadditions (Section D. 1.6.1.5.). 

Diethylhydroxyborane cannot be vacuum distilled without decomposition. Tetraethyldiboroxane and water are formed which then recombine at room temperature. Diethylhydroxyborane forms 1 1 addition compounds with carboxylic acids and acyloxydialkylboranes as evidenced by H-NMR spectroscopy below -30°. 

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