Acylation and carboxylation

The simplest procedures for 2-acylation involve reaction of an jV-protected 2-lithioindole with an acyl halide, anhydride or ester. Such reactions typically give good yields of 2-acylindoles. Table 10.3 presents some examples. Aryl 

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Sugino and S. Hibino, J. Chem. Soc. Chem. Commun. 1241 (19S0). 

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The reaction of lithio derivatives with appropriate electrophiles has been utilized in the preparation of alkyl, aryl, acyl and carboxylic acid derivatives. Representative examples of these conversions are given in Scheme 79. Noteworthy is the two-step method of alkylation involving reaction with trialkylborane followed by treatment with iodine (78JOC4684). 

In these compounds the following substituents can be present alkyl,alkenyl,aryl, halogen,sulfonic acid, amino, hydroxyalkyl, acyl, and carboxyl. The cleavages of 5,5 - (109) and 3,5 -diisoxazolyl (111) proceed similarly both isoxazole rings are cleaved in the former (109—> 110). ... 

Unsubstituted ODC are alkylated to 1,19-dialkyl-ODC with alkyl iodide or allyl bromide, while 1-ethoxycarbonyl- and l,19-bis(ethoxycarbonyl)-ODC are decarboxylated to 19-unsubstituted ODC and corrole respectively by alcoholic alkali. 19-Acyl and -carboxyl groups are also eliminated by alcoholic alkali (2 N KOH, EtOH, 60 °C) and NEt3-AcOH respectively. 2... 

The first step is a Friedel-Crafts acylation reaction. The use of a cyclic anhydride introduces both the acyl and carboxyl groups into the molecule. 

Nucleophilic Acylation and Carboxylation of Alkyl Halides and p-TOLUENESULFONATES WITH DiSODIUM TeTRAC ARBOITYLFERRATe ... 

TABLE XXXVII. 2-Pyrazolin-5-ones. Acyl and Carboxyl Derivatives and Sulfonyl SubBtituents on N-l... 

Since Kharasch reported radical-mediated carboxylation of saturated hydrocarbons with phosgene as a radical trap in the 1940s [39], no successful radical acylation and carboxylation reactions have appeared. In intermolecular radical acetylations, biacetyl was used as a radical trap (Scheme 18) [44]. The addition of an alkyl radical to the carbonyl carbon of biacetyl gives the methyl ketone along with an acetyl radical. 

A short review of photo-oxidation of a range of polymers by Faucitano and co-workers [30] summarised the understanding at the time of PET photolysis as a splitting of C-0 bonds in the ester gronps, with formation of acyl and carboxyl radicals, which themselves can lose carbon oxides to produce phenyl or alkyl radicals, or abstract hydrogen to produce aldehydes and carboxylic acids. When oxygen is present, the authors state that the autoxidation chain reaction will lead to formation of anhydrides and aldehydes, and to hydroxy-substituted phenyl species. 

Amidines and isothioureas as acyl and carboxyl transfer catalysts... 

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