Inductive effects carbonyls

Carboxylic acids are weak acids and m the absence of electron attracting substituents have s of approximately 5 Carboxylic acids are much stronger acids than alcohols because of the electron withdrawing power of the carbonyl group (inductive effect) and its ability to delocalize negative charge m the carboxylate anion (resonance effect)... 

Fluorinated Acids. This class of compounds is characterized by the strength of the fluorocarbon acids, eg, CF COOH, approaching that of mineral acids. This property results from the strong inductive effect of fluorine and is markedly less when the fluorocarbon group is moved away from the carbonyl group. Generally, their reactions are similar to organic acids and they find apphcations, particularly trifluoroacetic acid [76-05-1] and its anhydride [407-25-0] as promotors in the preparation of esters and ketones and in nitration reactions. 

For many years, resonance in caiboxylate ions was emphasized when explaining the acidity of carboxylic acids. Recently, however, it has been suggested that the inductive effect of the carbonyl group may be more important. It seems clear that, even though then- relative contributions may be a matter of debate, both play major roles. 

In transforming bis-ketone 45 to keto-epoxide 46, the elevated stereoselectivity was believed to be a consequence of tbe molecular shape — tbe sulfur ylide attacked preferentially from tbe convex face of the strongly puckered molecule of 45. Moreover, the pronounced chemoselectivity was attributed to tbe increased electropbilicity of the furanone versus the pyranone carbonyl, as a result of an inductive effect generated by tbe pair of spiroacetal oxygen substituents at tbe furanone a-position. ... 

The carbonyl group also possesses electrophilic properties at the carbon atom and nucleophilic properties at the oxygen atom. Nucleophilic attack of the carbonyl group is favored if this is attached to an aromatic ring (inductive effect) and there is also a methoxy or phenolic OH group present in the 4-position. Changing a neutral reaction medium by proton addition has the same effect. 

Delocalisation takes place (cf. 1,3-dienes, p. 13), so that an electron-deficient atom results at C3, as well as at C, as in a simple carbonyl compound. The difference between this transmission via a conjugated system, and the inductive effect in saturated system, is that here the effect suffers much less diminution by its transmission, and the polarity at adjacent carbon atoms alternates. 

As well as the C->-0 inductive effect in the bond joining the two atoms, the more readily polarisable it electrons are also affected (cf p. 22) so that the carbonyl group is best represented by a hybrid... 

CX3 is a good leaving group because of the electron-withdrawing inductive effect of the three halogen atoms this activates the carbonyl carbon atom in (100) to nucleophilic attack, and also stabilises the... 

The inductive effect of the carbonyl group (C=0 group) is responsible for the... 

The carbonyl group has a more powerful electron-attracting inductive effect than the CH2 group. 

The carbon atom of the carbonyl group of acetic acid bears a large positive charge, it adds its electron-withdrawing inductive effect to that of the oxygen atom of the hydroxyl group attached to it. 

The electron-withdrawing inductive effect of the carbonyl group also stabilizes the acetate ion, and therefore the acetate ion is a weaker base than the ethoxide ion. 

The reactivity of oximes is less than that of carbonyls, attributed to the inductive effect of OH on N. Nevertheless, they conform to the plot of Hart et al (1967). 

Effect of substituents of the carbonyl bond, (a) Inductive effect, X = H, OH,... 

For the cycloreduction of keto-enones, competitive 1,4-reduction in response to the reduced electrophilicity of the carbonyl partner is observed. Diones are more susceptible to addition by viture of inductive effects and the relief of di-... 

Another important site of structural variation in cephalosporins is C(3) (Table 5.4.J). Electron-withdrawing substituents at C(3) such as a Cl-atom or a MeO group increase base-catalyzed hydrolysis of cephalosporins by both resonance and inductive effects [92], For cephalosporins carrying 3-methylene-linked substituents with leaving group ability (e.g., acetate, thiol, or pyridine), it has been postulated that a concerted expulsion of the substituent facilitates the nucleophilic attack on the /3-lactam carbonyl group [104][105]. However, there are also arguments for a stepwise process in which the ex-... 

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