Ionic Liquids as Novel Media and Catalysts for Electrophilic/Onium Ion Chemistry and Metal-Mediated Reactions

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An efficient and chemoselective formylation method for amines has been reported by using formic acid with tetramethylguanidine trifluoroacetate as catalyst and solvent.

An efficient and chemoselective formylation method for amines has been reported by using formic acid with tetramethylguanidine trifluoroacetate as catalyst and solvent. Various amines including OH-bearing analogs such as aminoacids and hydroxylamines were converted to the N-formylated derivatives with excellent reported yields.

 

Alcohols underwent mild O-formylation with ethyl formate at room temperature by using [BMIM][HSO4] as catalyst and afforded moderate to good yields of the corresponding formates.129 The ability to selectively formylate a primary alcohol in the presence of a tertiary alcohol or a phenol is a positive feature of this protocol.

 

Imidazolium-based ILs served as catalyst for the formylation of aliphatic/aromatic amines and/or alcohols130,131 with either CO or formic acid as formylating agent, in moderate to excellent yields.

 

A metal- and acid-free room temperature formylation method for amines that employs CO2 and phenylsilane and [BMIM]Cl as catalyst has been reported.132 Aromatic amines underwent smooth monoformylation, whereas the aliphatic counterpart gave both mono- and diformylated products. NMR studies of the IL and phenylsilane mixture suggested that IL activates the silane's Si-H bond for CO2 insertion, and this leads to the formation of formamide.

 

The terminal methyl carbon of a fatty acid is designated the ω carbon, as it occupies a position on the acyl chain the furthest from the α carbon (which is adjacent to the carboxylic acid group) (Fig. 2). Based on the position of the double bond closest to the ω carbon, unsaturated fatty acids commonly found in nature can be divided into three major series: ω-3, ω-6, and ω-9. In more modern fatty acid nomenclature, the ω has been superseded by n, and, hence, fatty acids fall into the n-3, n-6, and n-9 series. While n-9 fatty acids are of limited importance, the n-6 and n-3 fatty acids are widely distributed in animal, plant, and microbial lipids. Furthermore, some of these fatty acids play key roles in human growth, development, and health. It is important to note that the public awareness of the health benefits of dietary polyunsaturated fatty acid (PUFA) has resulted in a concerted effort on the part of food manufacturers to supplement (or highlight) the n-3 content of many foods. In this context, the older designation remains in place so consumers are informed of, and discuss, the ω-3 or omega three content of foods.

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