Aliphatic saturated carbon

In general, substituents removed from the ring by two or more saturated carbon atoms undergo normal aliphatic reactions, and substituents attached directly to fused benzene rings or aryl groups undergo the same reactions as do those on normal benzenoid rings. 

Most of the kinetic measures of solvent effects have been developed for the study of nucleophilic substitution (Sn) at saturated carbon, solvolytic reactions in particular. It may, therefore, be helpful to give a brief review of aliphatic nucleophilic substitution. Two mechanistic routes have been clearly identified. One of these is shown by... 

Volume 8 Volume 9 Volume 10 Volume 12 Volume 13 Proton Transfer Addition and Elimination Reactions of Aliphatic Compounds Ester Formation and Hydrolysis and Related Reactions Electrophilic Substitution at a Saturated Carbon Atom Reactions of Aromatic Compounds Section 5. POLYMERISATION REACTIONS (3 volumes)... 

Several distinct mechanisms are possible for aliphatic nucleophilic substitution reactions, depending on the substrate, nucleophile, leaving group, and reaction conditions. In all of them, however, the attacking reagent carries the electron pair with it, so that the similarities are greater than the differences. Mechanisms that occur at a saturated carbon atom are considered first. By far the most common are the SnI and Sn2 mechanisms. 

The chemical reactions of sulphonyl nitrenes include hydrogen abstraction, insertion into aliphatic C—H bonds, aromatic substitution , addition to olefinic double bonds, trapping reactions with suitable nucleophiles, and Wolff-type rearrangement. Hydrogen-abstraction from saturated carbon atoms is usually considered to be a reaction typical of triplet... 

Nucleophilic aliphatic substitution is the displacement from saturated carbon of a group with its bonding electrons by a group with an extra pair of electrons (Equation 4.2). 

Carbonyl compounds will be taken in this chapter to mean any organic compound that contains at least one carbon-oxygen double bond where we limit the substitution to only saturated aliphatic, saturated alicyclic and aryl hydrocarbyl groups. Carbonyl compounds with a variety of unsaturated substituents have earlier been discussed within the context of enones4. Non-hydrocarbyl substituents, X , may be directly attached to the carbonyl and elsewhere in the molecule. The first type of species, RCOX, is alternatively identified as acyl derivatives such as carboxylic acids and their esters, halides and amides and have already been discussed in a recent Patai thermochemistry... 

Our principal target in P-450 mimics was the selective oxidation of saturated carbons directed by geometric control, not by intrinsic reactivity. In our first study, we examined selective geometrically controlled attack on aliphatic C-H bonds by photo-excited benzophenones [145]. In a process we labeled remote oxidation", photolysis of a long-chain ester 69 of benzophenone-4-carboxylic acid afforded insertion into CH2 groups far into the chain. 

The asymmetry parameters of substituted chlorobenzenes and iodobenzenes have been discussed above in Section III.A.3 (Tables 4 and 5). The asymmetry parameters of several systems are discussed below carbonyl chlorides in Section III.B.4, a variety of substituted vinyl chlorides in Section III.B.9 and methylene dichloride and chloroform in Section III.B.lO.c. There remain a number of measurements of asymmetry parameters30-33, mainly of aliphatic systems, that are not covered elsewhere and these are listed in Table 7. It will be seen that the asymmetry parameters of chlorine atoms bonded to saturated carbon atoms are always small, of the order of 0.05 or less, while if the chlorine atom is bonded to an sp2-hybridized carbon atom then the asymmetry parameter is generally equal to or greater than 0.1. 

Protonation of a saturated carbon atom is possible only if an organo-metallic bond can be broken at the same time in an aliphatic electrophilic substitution (see Vol. 12, Chap. 2), viz. 

---