Phenols aminocarbonylation

Immobilized, highly reactive phenyl esters can be prepared by acylating resin-bound 4-acyl-2-nitrophenol (Entry 4, Table 3.13 [285-288]) or 4-(aminocarbonyl)-2,3,5,6-tetrafluorophenol (Entries 7 and 8, Table 3.13). These esters are similar to oxime esters (see Section 3.3.3.3), and even react with weak nucleophiles such as anilines or alcohols. This type of linker is not, therefore, well suited for long synthetic sequences on insoluble supports, but only for the preparation of simple acid derivatives. Because cleavage yields the unchanged phenol, these resins can be reused several times, which renders this strategy of preparing acid derivatives quite cost-effective. 

Salicylanilides (35) have also been prepared by o-aminocarbonylation of phenols with phenyl isocyanate. Thus, reaction of the lithium salt of phenol (38) with phenyl isocyanate in the presence of aluminum chloride in refluxing xylene affords 15-30% yields of the salicylanilides [66]. 

In 2013, Bhanage designed and developed an IL-immobilized palladium catalyst 183 and successfully employed in carbonylation reactions, including alkoxycarbonylation, phenoxycarbonylation, and aminocarbonylation ( heme 24) [67]. Alkoxycarbonylation reaction between aryl iodide 184 and alcohol or phenol or amine was performed in an autoclave pressurized with 0.5 MPa of carbon monoxide. Current process would be useful for the utilization of carbon monoxide for synthesis of valuable chemicals from simple starting materials with the use of recyclable catalyst. Furthermore, this catalytic system avoids use of phosphine ligands. The IL-supported palladium catalyst was recycled up to four successive recycles. 

An important use of H CHO has been found in amino[ " C]methylations of nucleophiles in the presence of primary and secondary amines (Mannich reaction). Nucleophilic substrates include C—H acidic aliphatic compounds (e.g. aldehydes, ketones, esters, nitroalkanes and nitriles), and reactive aromatic and heteroaromatic substrates such as indoles, furans and phenols. The amino[ C]methylations of some C—H acidic methyl, methylene and methine substrates are exemplified in Figure 5.44. The immediate products, alkyl- or dialkylamino[ C]methylene derivatives ( Mannich bases ), can undergo a number of useful synthetic transformations. Condensation of H CHO with acetophenone and dimethylamine provided the carbon- 14-labeled /3-aminoketone 147 in 51 % yield. /3-Aminocarbonyl compounds such as 147. whQe stable at room temperature, can eliminate... 

The aminocarbonylation of phenols with carbon monoxide and ammonia has been achieved using palladium catalysis. After in situ conversion of the phenols to the corresponding nonaflates, oxidative addition to the palladium gives an aryl palladium complex which undergoes carbon monoxide insertion. Nucleophilic attack of ammonia results in the formation of the benzamide. ... 

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