Mechanisms for nucleophilic aliphatic

Mechanisms for nucleophilic aliphatic substitution at glycosides, 41, 277 Mechanisms of hydrolysis and rearrangements of epoxides, 40, 247 Mechanisms of oxygenations in zeolites, 42, 225 Mechanisms, nitrosation, 19, 381... 

The mechanism shown in Reaction 4.7 is still widely accepted as one of the two general mechanisms for nucleophilic aliphatic substitution. It is widely accepted today because in the intervening years a large bulk of experimental evi-... 

Recognition of the duality of mechanism for nucleophilic aliphatic substitution, formulation of the mechanisms themselves, and analysis of the factors influencing competition between them—all are largely due to Sir Christopher Ingold (of University College, London) and the people who worked with him and this is only a fraction of their total contribution to the theory of organic chemistry. 

The two mechanisms for Friedel-Crafts alkylation are not dissimilar to the two mechanisms for nucleophilic aliphatic substitution. In an S,j1 mechanism, a carbocation is generated from an alkyl halide before the nucleophile attacks, but in an S 2 reaction the halide departs simultaneously with the nucleophile attacking the R group. In the Friedel-Crafts reaction, benzene behaves as the nucleophile. 

This chain reaction is analogous to radical chain mechanisms for nucleophilic aliphatic nucleophilic substitution that had been suggested independently by Russell and by Komblum and their co-workers. The descriptive title SrnI (substitution radical-nucleophilic unimolecular) was suggested for this reaction by analogy to the SnI mechanism for aliphatic substitution. The lUPAC notation for the SrkjI reaction is (T -t- Dm -t- An), in which the symbol T refers to an electron transfer. When the reaction was carried out in Ihe presence of solvated electrons formed by adding potassium metal to the ammonia solution, virtually no aryne (rearranged) products were observed. Instead, reaction of 95c produced only 98 (40%) and 94 (40%) but no 99, and reaction of 96c produced 99 (54%) and 94 (30%) with only a trace of 98. ... 

Mechanism and structure, in organic electrochemistry, 12, 1 Mechanism of the dissociative reduction of C—X and X—X bonds pCl/40, S), kinetics and, 36, 85 Mechanisms for nucleophilic aliphatic substimtion at glycosides,... 

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