Amides intramolecular carbonylation

Carbonylation of halides in the presence of primary and secondary amines at I atm affords amides[351j. The intramolecular carbonylation of an aryl bromide which has amino group affords a lactam and has been used for the synthesis of the isoquinoline alkaloid 498(352], The naturally occurring seven-membered lactam 499 (tomaymycin, neothramycin) is prepared by this method(353]. The a-methylene-d-lactam 500 is formed by the intramolecular carbonylation of 2-bromo-3-alkylamino-l-propene(354]. 

To avoid the interference from intramolecular REDOR dephasing, peptides with 15NH, labels could be mixed with peptides with 13COy labels in a 1 1 ratio before fibrillization, where i and j denote the residues with isotopic enhancement at the amide and carbonyl sites, respectively. If an in-register parallel (3-sheet is considered as the hypothetical structure, the most adequate model for the analysis of the 13C 15N REDOR data measured for the case of i = j should be a 15N-13C-15N spin system, where the NCN angle is ca. 127° and the two 15N-13C distances are 5.3 and 5.5 A (Fig. 4a). For the case of i = j + 1, the NCN angle should be 154° and the two 15N-13C distances 4.2 and 5.6 A. Other combinations of i and j for an... 

H-donor for both the intramolecular hydrogen bond with the amide linker carbonyl the carboxylic acid group is deprotonated. 

The diastereoselective formation of a cyclic array of intramolecular hydrogen bonds between amide and carbonyl functions at the narrow rim was also observed for the tetraamides 121 and for similar 1,3-di- or monoamides.242... 

An efficient route for the construction of chiral bicyclo[4.3.1]decanes (215) has been developed " employing an acid-catalysed intramolecular carbonyl ene reaction see (214) —> (215). Optically active bicyclic lactones have been prepared by a highly diastereo- and enantio-selective ene reaction of cyclopentenes with ethyl glyoxylate. A one-pot allylic amidation which employs the ene reaction of acylnitroso compounds (216) with electron-rich alkenes has been reported see Scheme 52. 

Scheme 15 Proposed mechanism for intramolecular carbonylation of amides via sp C-H activation...

In 2012, Mark J. Kurth et al. developed an operationally simple, one-pot, two-step cascade method to afford quinazolino[l,2,3]triazolo[l,4]benzodiazepines 112 (Scheme 4.43) [44]. Fascinatingly, this unique, atom-economical transformation engaged five reactive centers (amide, aniline, carbonyl, azide, and alkyne) and employed environmentally benign iodine as a catalyst. The method seemed to proceed via sequential quinazolinone-forming condensation and intramolecular azide-alkyne 1,3-dipolar cycloaddition reactions. The substrate... 

The use of a vinylphosphonium salt as the source of the QQ fragment instead of the more commonly employed 1,2-dicarbonyl substrate is illustrated by the pyrrole synthesis in Scheme 79b (8UOC2570). A particularly interesting feature is the intramolecular Wittig reaction with an amide carbonyl group. A very useful synthesis of pyrroles depends upon the addition of the anion of p-toluenesulfonylmethyl isocyanide (TOSMIC) to a,/3-unsatur-... 

In this series of amides, hydrolysis or aminolysis of a simple ester, cleavage of a silyl groups a cis/trans isomerization, or reduction of a quinone to a hydro-quinone exposes an alcohol that then induces deprotection by intramolecular addition to the amide carbonyl. 

An interesting reaction ensues when the intermediate synthetic precursor (65) to synthon 60 is heated with phenylenediamine. The reaction can be rationalized as involving initial enamine-imine formation (66), followed by intramolecular attack on the ester carbonyl groups resulting in carbamate formation (67), which carbamate undergoes intramolecular trans-amidation to give urea 66. Other scenarios can be proposed and defended, but the net result is formation... 

There are two important rhodium-catalyzed transformations that are broadly used in domino processes as the primary step. The first route is the formation of keto carbenoids by treatment of diazo keto compounds with Rh11 salts. This is then followed by the generation of a 1,3-dipole by an intramolecular cyclization of the keto carbenoid onto an oxygen atom of a neighboring keto group and an inter- or intramolecular 1,3-dipolar cycloaddition. A noteworthy point here is that the insertion can also take place onto carbonyl groups of aldehydes, esters, and amides. Moreover, cycloadditions of Rh-carbenes and ring chain isomerizations will also be discussed in this section. 

The preparation of 3-vinylpyrroles was investigated utilizing the Horner-Wads worth-Emmons reaction with 3-formyl-lV-tosylpyrrole <06S1494>. The intramolecular acylation of pyrrole-2-Weinreb amides provided access to novel indolizinone derivatives <06T6182>. The amidation of pyrrole-2-carbonyl chloride was utilized as a key step in the preparation of pyrrole-oxazole analogue 90 of the insecticide Pirate <06S1975>. 

Similarly, amides react with an intramolecular 7r-allylpalladium through the carbonyl oxygen to form oxazolines in... 

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