Acyl mercurials

The O-alkylation of acyl mercurials produces cationic carbene complexes (Gerhart and Schollkopf, 1967). Similar procedures have been used to prepare... 

Mercury can be used to dehalogenate acyl halides to ketenes when a halogen IS present next to the COCl group [67] (equation 35)... 

The benzodithiepines 126 and 127 have been used as formyl and acyl anion equivalents, respectively, although the range of electrophiles was restricted to alkyl halides (75S720) and epifluorohydrin (72TL1837). The carbonyl products were formed by hydrolysis with either mercury or copper salts. 

R2NC1, 91, 92 phenyl acetate, Fries rearrangement of, 475 phenyacetyl halides, acylation by, 173 2-phenylbenzoic acid, cycliacylation, 185 phenyl ethers, alkylation of, 149 —, bromination of, 130 —, hydrogen exchange with, 260 —, rearrangement of, 476 phenyl ethyl mercury, mercuridemercuration of, 359, 360... 

Triple bonds can give enol esters or acylals when treated with carboxylic acids. Mercuric salts are usually catalysts, and vinylic mercury compounds... 

Organomercury reagents do not react with ketones or aldehydes but Lewis acids cause reaction with acyl chlorides.187 With alkenyl mercury compounds, the reaction probably proceeds by electrophilic attack on the double bond with the regiochemistry being directed by the stabilization of the (3-carbocation by the mercury.188... 

In a,jS-unsaturated stannyl esters the acyl moiety is displaced by mercury(II) salts without affecting carbon-carbon double bonds, as shown in reaction 71322. 

The procedure described here allows for a convenient and efficient preparation in very high yields of large quantities of bromides from carboxylic acids containing an olefinic functionality. The Hunsdiecker reaction is traditionally accomplished by treating anhydrous silver carboxylates with bromine or iodine.2 Heavy metal salts such as mercury,3 lead,4 and thallium5 have also been used successfully as well as tert-butyl hypoiodite.6 The major disadvantages associated with the above methods, such as use of heavy metal salts and non-tolerance towards olefins, has led to the development of a more versatile method using O-acyl thiohydroxamates.7 8 The O-... 

Mechanistic aspects of the reduction of benzyl halides at mercury have been extensively investigated [35, 38]. From the reduction of benzyl iodide at platinum, Koch and coworkers [39] obtained toluene, bibenzyl, and hydrocinnamonitrile. Electrolysis of benzyl chloride in the presence of acyl chlorides can be used to synthesize alkyl benzyl ketones [40], whereas alcohols are formed by electrolysis of... 

Reduction of benzoyl chloride at mercury yields an acyl radical that dimerizes to form benzil. As quickly as it forms, benzd accepts an electron to form an anion radical that is acylated by a molecule of benzoyl... 

Phenylacetyl chloride and hydrocin-namoyl chloride are reduced at mercury to form both acyl radicals and acyl anions as intermediates [76]. From electrolyses of phenylacetyl chloride, the products include 1,4-diphenyl-2-butene-2,3-diol diphenylac-etate, phenylacetaldehyde, toluene, 1,3-diphenylacetone, and l,4-diphenyl-2,3-butanediol, and analogous species arise from the reduction of hydrocinnamoyl chloride. Reduction of phthaloyl dichloride is a more complicated system [77] the electrolysis products are phthalide, biph-thalyl, and 3-chlorophthalide, but the latter compound undergoes further reduction to give phthalide, biphthalyl, and dihydrobi-phthalide. 

Reduction of 1-adamantanecarbonyl chloride at carbon or mercury leads to the quantitative formation of 1-adamantanecarboxaldehyde [80]. Mubarak [81] investigated the reduction of 2-thiophenecarbonyl chloride at both carbon and mercury the starting material appears to undergo a two-electron reduction to form an acyl anion, which leads to l,2-di(2-thienyl)ethene-l,2-diol di(2-thiophenecarboxylate) as the major product and to 2-thiophenecarboxaldehyde as the minor product. 

Idoxuridine Idoxuridine, 5-iodo-1 -(2-deoxyyribofuranosyl)pyrimidin-2,4-(l//.3//)-dione (36.1.14), is synthesized by the following scheme. 5-lodouracil is acylated with acetic anhydride to make l-acetyl-5-iodouracil (36.1.11). Treating this with mercury(ll) acetate gives... 

Benzylquinoxaline (62) is the only product isolated from the homolytic benzylation of quinoxaline with dibenzyl mercury.73 Gardini and Minisci found that homolytic alkylation,74 acylation,75 cr-oxy-alkylation,76 carboxylation,77 and <5-aminoalkylation78 of quinoxaline always gave the 2-substituted product. When a mixture of quinoxaline and ferrous sulfate is treated with A-chlorodi-n-butylamine, exclusive 2-substitution occurs in 50% sulfuric acid, but in concentrated acid a... 

Benzoxathiolium salts have proven to be effective masked acylating agents (79S223). 2-Substituted 1,3-benzoxathiolium tetrafluoroborates have now been utilized in the preparation of esters. Reaction of the salt (334) with two equivalents of an alcohol gave the 2-alkoxy-2-alkyl-benzoxathiole (335). Hydrolysis of (335) with red mercury(II) oxide and boron trifluoride etherate in aqueous THF delivered ethyl benzoate in excellent yield (Scheme 72). 

Thenaldehyde (thiophene-2-carbaldehyde) is readily available via the Vilsmeier-Haack reaction of DMF with thiophene catalyzed by phosphorus oxychloride. The Sommelet reaction with 2-chloromethylthiophene also gives reasonable yields (63AHC(l)l). Likewise, thiophene is readily acylated with acyl anhydrides or acid chlorides (equation 14), using mild Friedel-Crafts catalysts, such as tin(IV) chloride, zinc chloride, boron trifluoride, titanium tetrachloride, mercury(II) chloride, iodine and even silica-alumina gels or low-calcium-content montmorillonite clays (52HC(3)l). 

N-Acylated Cys derivatives 32 on treatment with silver(I) oxide or silver(I) carbonate/1061 mercury(II) oxide/1071 iron salts/1081 or DCC1 091 undergo a (3-elimination reaction to yield AAla derivatives 33. The various (3-leaving groups that have been reported include sulfoxide/1101 sulfone/1111 5,5-dimethylsulfonium [Me2+S]/1121 2,4-dinitrophenylsulfanyl11131 and 5-dimethylphosphinothionyl11141 (Scheme 12). 

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