Carboxylic acid halides aldehydes

Arene(tricarbonyl)chromium complexes, 19 Nickel boride, 197 to trans-alkenes Chromium(II) sulfate, 84 of anhydrides to lactones Tetrachlorotris[bis(l,4-diphenyl-phosphine)butane]diruthenium, 288 of aromatic rings Palladium catalysts, 230 Raney nickel, 265 Sodium borohydride-1,3-Dicyano-benzene, 279 of aryl halides to arenes Palladium on carbon, 230 of benzyl ethers to alcohols Palladium catalysts, 230 of carboxylic acids to aldehydes Vilsmeier reagent, 341 of epoxides to alcohols Samarium(II) iodide, 270 Sodium hydride-Sodium /-amyloxide-Nickel(II) chloride, 281 Sodium hydride-Sodium /-amyloxide-Zinc chloride, 281 of esters to alcohols Sodium borohydride, 278 of imines and related compounds Arene(tricarbonyl)chromium complexes, 19... 

This latter thought has an important consequence if compounds with C=0 double bonds are sorted in decreasing order of resonance stabilization of their C=0 group they are at the same time sorted according to their increasing propensity to enolization. So as the resonance stabilization of the C=0 double bond decreases from 22 kcal/mol to somewhere near zero in the order carboxylic acid amide > carboxylic acid ester/carboxylic acid > ketone > aldehyde > carboxylic acid chloride/-bromide, the enol content increases in this same order (Figure 12.2). These circumstances immediately explain why no enol reactions whatsoever are known of carboxylic acid amides, virtually none of normal carboxylic acid esters/carboxylic acids, but are commonly encountered with ketones, aldehydes and carboxylic acid halides. 

Carboxylic acid halides/aluminum halides 1,1-Dihalides from aldehydes s. 18,603 RCOHaUAlHals GHO GHHalg... 

Classification and Organization of Reactions forming Difunctional Compounds. This new chapter considers all possible difunctional compounds formed from the groups acetylene, carboxylic acid, alcohol, aldehyde, amide, amine, ester, ether, epoxide, halide, ketone, nitrile, and olefin. Reactions that form difunctional compounds are classified into sections on the basis of the two functional groups of the product. The relative positions of the groups do not affect the classification. Thus preparations of 1,2-aminoalcohols, 1,3-aminoalcohols and 1,4-aminoalcohols are included in a single section. It is recommended that the following illustrative examples of the classification of difunctional compounds be scrutinized closely. 

Carboxylic acid halides/aluminum halide 1,1-Dihalidcs from aldehydes... 

Label the structures in the S nithetic Transformations above according to their functional group category. Choose from alcohol (specify 1°, 2°, or 3° if indicated), amine, aldehyde, ketone, amide, ester, carboxylic acid, carboxylate, acid halide, or acid anhydride. 

Organoboron compounds are known as useful reagents or reaction intermediates for the preparation of a wide variety of functional compounds such as alcohols, amines, carboxylic acids, ketones, aldehydes, olefins, and halides (1-3). For several decades. Brown and his coworkers have studied this chemistry. 

The conversion of carboxylic acid derivatives (halides, esters and lactones, tertiary amides and lactams, nitriles) into aldehydes can be achieved with bulky aluminum hydrides (e.g. DIBAL = diisobutylaluminum hydride, lithium trialkoxyalanates). Simple addition of three equivalents of an alcohol to LiAlH, in THF solution produces those deactivated and selective reagents, e.g. lithium triisopropoxyalanate, LiAlH(OPr )j (J. Malek, 1972). 

The dianions derived from furan- and thiophene-carboxylic acids by deprotonation with LDA have been reacted with various electrophiles (Scheme 64). The oxygen dianions reacted efficiently with aldehydes and ketones but not so efficiently with alkyl halides or epoxides. The sulfur dianions reacted with allyl bromide, a reaction which failed in the case of the dianions derived from furancarboxylic acids, and are therefore judged to be the softer nucleophiles (81JCS(Pl)1125,80TL505l). 

Chiral oxazolines developed by Albert I. Meyers and coworkers have been employed as activating groups and/or chiral auxiliaries in nucleophilic addition and substitution reactions that lead to the asymmetric construction of carbon-carbon bonds. For example, metalation of chiral oxazoline 1 followed by alkylation and hydrolysis affords enantioenriched carboxylic acid 2. Enantioenriched dihydronaphthalenes are produced via addition of alkyllithium reagents to 1-naphthyloxazoline 3 followed by alkylation of the resulting anion with an alkyl halide to give 4, which is subjected to reductive cleavage of the oxazoline moiety to yield aldehyde 5. Chiral oxazolines have also found numerous applications as ligands in asymmetric catalysis these applications have been recently reviewed, and are not discussed in this chapter. ... 

Notable examples of general synthetic procedures in Volume 47 include the synthesis of aromatic aldehydes (from dichloro-methyl methyl ether), aliphatic aldehydes (from alkyl halides and trimethylamine oxide and by oxidation of alcohols using dimethyl sulfoxide, dicyclohexylcarbodiimide, and pyridinum trifluoro-acetate the latter method is particularly useful since the conditions are so mild), carbethoxycycloalkanones (from sodium hydride, diethyl carbonate, and the cycloalkanone), m-dialkylbenzenes (from the />-isomer by isomerization with hydrogen fluoride and boron trifluoride), and the deamination of amines (by conversion to the nitrosoamide and thermolysis to the ester). Other general methods are represented by the synthesis of 1 J-difluoroolefins (from sodium chlorodifluoroacetate, triphenyl phosphine, and an aldehyde or ketone), the nitration of aromatic rings (with ni-tronium tetrafluoroborate), the reductive methylation of aromatic nitro compounds (with formaldehyde and hydrogen), the synthesis of dialkyl ketones (from carboxylic acids and iron powder), and the preparation of 1-substituted cyclopropanols (from the condensation of a 1,3-dichloro-2-propanol derivative and ethyl-... 

In the course of this study, the authors determined /Lvalues for dibenzyl, methyl phenyl, methyl p-nitrophenyl, di-p-tolyl, di-isopropyl and tetramethylene sulphoxides and for diethyl, dipropyl and dibutyl sulphites. The /Lscales are applied to the various reactions or the spectral measurements. The /Lscales have been divided into either family-dependent (FD) types, which means two or more compounds can share the same /Lscale, family-independent (FI) types. Consequently, a variety of /Lscales are now available for various families of the bases, including 29 aldehydes and ketones, 17 carboxylic amides and ureas, 14 carboxylic acids esters, 4 acyl halides, 5 nitriles, 10 ethers, 16 phosphine oxides, 12 sulphinyl compounds, 15 pyridines and pyrimidines, 16 sp3 hybridized amines and 10 alcohols. The enthalpies of formation of the hydrogen bond of 4-fluorophenol with both sulphoxides and phosphine oxides and related derivatives fit the empirical equation 18, where the standard deviation is y = 0.983. Several averaged scales are shown in Table 1588. 

Aldehydes have been prepared from carboxylic acids or acyl halides by first converting them to certain types of amides that are easily reducible. The following are some examples ... 

Similar additions have been successfully carried out with carboxylic acids, anhydrides, acyl halides, carboxylic esters, nitriles, and other types of compounds. These reactions are not successful when the alkene contains electron-withdrawing groups such as halo or carbonyl groups. A free-radical initiator is required, usually peroxides or UV light. The mechanism is illustrated for aldehydes but is similar for the other compounds ... 

Primary, secondary, and tertiary aliphatic amines have been cleaved to give aldehydes, ketones, or carboxylic acids with aqueous bromine and with neutral permanganate. The other product of this reaction is the amine with one less alkyl group. In a different type of procedure, primary alkyl primary amines can be converted to ge/n-dihalides, RCH2NH2 —> RCHX2 (X =Br or Cl), by treatment with an alkyl nitrite and the anhydrous copper(I) halide. 

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