Functional groups carbonyl

Trifluoromethyl)trimethylsilane has been prepared by a modification5 of the procedure originally published by Ruppert.4 The optimized yield is 75%. Other less convenient methods are also available for its preparation. (Trifluoromethyl)trimethylsilane acts as an in situ trifluoromethide equivalent under nucleophilic initiation and reacts with a variety of electrophilic functional groups. Carbonyl compounds such as aldehydes, ketones and lactones react rather readily5 7 with (trifluoromethyl)trimethylsilane under fluoride initiation. The reagent also reacts with oxalic esters,8 sulfonyl fluorides,9 a-keto esters,10 fluorinated ketones,11 and... 

In creating synthetic routes for the development of drug molecules, the synthetic chemist wants to create a molecular entity in which functional groups (carbonyls, amines, etc.) are correctly positioned in three-dimensional space this will enable the creation of functional biophoric fragments such as the pharmacophore. The synthetic chemist has ten general classes of reactions available for such synthetic tasks ... 

The relative reactivity of the alcohol and amine in the example just given could be overturned by conducting a reaction under thermodynamic control. In kinetically controlled reactions, the idea that you can conduct chemoselective reactions on the more reactive of a pair of functional groups— carbonyl-based ones, for example—is straightforward. But what if you want to react the less reactive of the pair There are two commonly used solutions. The first is illustrated by a compound needed by chemists at Cambridge to study an epoxidation reaction. They were able to make the following diol, but wanted to acetylate only the more hindered secondary hydroxyl group. 

Since monosaccharide.s contain only two kinds of functional groups, carbonyls and hydroxyls, most of the chemistry of monosaccharides is the now familiar chemistry of these two groups. 

We now turn to two reactions, the McMurry and metathesis, that have the same disconnection but both reagents have identical functional groups carbonyls for the McMurry and alkenes for metathesis. These methods have the advantage of simplicity but there are obvious problems of selectivity. 

Moreover, NMR was revolutionary in provoking a Gestalt switch (to borrow Kuhn s phraseology) in the chemists perceptions. Earlier, molecules were identified by their functional groups, carbonyls, hydroxyls, and the like, which were like beacons (as reflected in chemical nomenclature, in its affixes and priorities). Now, especially at the beginning of... 

Sugars contain an aldehyde or ketone functional group (carbonyl group, C=0) as well as several hydroxyl groups (—OH). 

The selection rule for IR spectroscopy is that for absorption to occur, the molecular dipole must change during the course of the vibration. Thus, simple diatomic molecules such as Oj do not absorb. The most intense absorptions involve polar functional groups—carbonyl groups absorb more strongly than alkenes, and nitriles more strongly than alkynes. 

The most important technical applications of catalytic hydrolysis and acylation involve technical enzymes, as used in food processing, washing powders, or derace-misations. Especially the latter application has also found significant application in chemical synthesis. The kinetic resolution of chiral, racemic esters, anhydrides, or alcohols relies on the faster conversion of only one substrate enantiomer by the chiral catalyst, whereas the other enantiomer ideally remains unchanged. A special case within kinetic resolutions is the desymmetrization of prochiral mexo-compounds like mera-anhydrides (2) or meso-diols, (5) that requires a selective conversion of one of the two enantiotopic functional groups (carbonyl or OH-group, Scheme 7.1). 

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