Ethers reaction with acyl halides

Enol Ethers and Esters 0-15 O-Alkylation of carbonyl compounds with diazo alkanes 0-17 Transetherification 0-20 Reaction between acyl halides and active hydrogen compounds 0-23 Transesterification 0-24 Acylation of vinylic halides 0-94 Alkylation with ortho esters 0-107 O-Acylation of 1,3-dicarbonyl compounds... 

Because of the special structural requirements of the resin-bound substrate, this type of cleavage reaction lacks general applicability. Some of the few examples that have been reported are listed in Table 3.19. Lactones have also been obtained by acid-catalyzed lactonization of resin-bound 4-hydroxy or 3-oxiranyl carboxylic acids [399]. Treatment of polystyrene-bound cyclic acetals with Jones reagent also leads to the release of lactones into solution (Entry 5, Table 3.19). Resin-bound benzylic aryl or alkyl carbonates have been converted into esters by treatment with acyl halides and Lewis acids (Entry 6, Table 3.19). Similarly, alcohols bound to insoluble supports as benzyl ethers can be cleaved from the support and simultaneously converted into esters by treatment with acyl halides [400]. Esters have also been prepared by treatment of carboxylic acids with an excess of polystyrene-bound triazenes here, diazo-nium salts are released into solution, which serve to O-alkylate the acid (Entry 7, Table 3.19). This strategy can also be used to prepare sulfonates [401]. 

Silyl ethers of aliphatic alcohols are inert towards strong bases, oxidants (ozone [81], Dess-Martin periodinane [605], iodonium salts [610,611], sulfur trioxide-pyridine complex [398]), and weak acids (e.g., 1 mol/L HC02H in DCM [605]), but can be selectively cleaved by treatment with HF in pyridine or with TBAF (Table 3.32). Phenols can also be linked to insoluble supports as silyl ethers, but these are less stable than alkyl silyl ethers and can even be cleaved by treatment with acyl halides under basic reaction conditions [595], Silyl ether attachment has been successfully used for the solid-phase synthesis of oligosaccharides [600,601,612,613] and peptides [614]. 

In related studies carried out by Gladysz and coworkers, the anionic silyl complex [(CO)4FeSiMe3] was found to react relatively cleanly with acyl halides, producing silyl enol ethers. The reaction with acetyl bromide gives a 70% yield of acetaldehyde trimethylsilyl enol ether (equation 89). An observed intermediate in this reaction was the... 

DIETHYLENE GLYCOL n-HEXYL ETHER (112-59-4) Combustible liquid (flash point 285°F/141°C cc). Violent reaction with oxidizers, permanganates, peroxides, ammonium persulfate, bromine dioxide, sulfuric acid, nitric acid, perchloric acid, and other strong acids. Incompatible with acyl halides, aliphatic amines, alkalis, boranes, isocyanates. 

Polymerization of pPL with a variety of initiators is a terminationless process. Lyudvig a.o. have mostly contributed to our present knowledge of the influence of reaction variables on the rates of polymerization 24 27). They obtained quantitative yields in the polymerization of lactones using bulky complex counterions, like SbClf1. Thus, the decomposition of these anions, leading to transfer and termination in the polymerization of cyclic ethers and acetals, does not lead to side reactions in the polymerization of lactones. This can be ascribed to reversible reactions between acyl halides plus Lewis acids and the acylium cation 28) ... 

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. 

Thallium(I) Compounds. Carboxylic anhydrides can be prepared by the reaction of acyl or aroyl halides in ether with thallium(I) carboxylates (26) ... 

Some acyl halides are reactive enough to effect Friedel-Crafts acylation on the neutral heterocycles without a catalyst. For pyrrole such reactions are known, for example, with trifluoroacetyl chloride and trichloroacetyl chloride. Indole reacts smoothly in cold ether with oxalyl chloride and on heating with acetic anhydride. Some examples of these types of acylation are collected in Table 10. 

Alkyl halides, acyl halides, anhydrides, and related substances. It was discovered as early as 1861 by Rcboul and Luurenool<4t> that epicblorohydrin may be caused to react with ethyl bromide on heating in a sealed tube to an elevated temperature. The product isolated from this condensation was ]-broJHo-3-chloro-2-ethoxyprt>pane. Some year later Paalli6 extended this reaction to include also methyl iodide, ethyl iodide, n-propyl iodide, and isopropyl iodide do2-propunol was formed. 

Similarly, acetals were converted to ethers (113,114), ketones to tertiary alcohols (111), and acyl halides to ketones (113). The reaction of Me3SiPl with 1-hexanal has been used as a key step in the total synthesis of the sperimidine alkaloid anhydrocannabisativine (115). 

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