Ring closure reactions. Part 6. Intermolecular models for intramolecular reactions. Reactions between long-chain alkanoate ions and alkyl bromides as intermolecular analogues of the lactonization of ω-bromoalkanoate ions
Abstract
The search for a general intermolecular model for lactonization of the anions of straight-chain ω-bromoalkanoic acids led to the determination of the rate constants of the SN2 reaction between some alkanoate ions and alkyl bromides, involving straight-chains of varying lengths up to C18 in both reactants. The experimental results show the appearance of a slight rate-enhancing effect on increasing chain length which may be attributed, at least in part, to lyophobic interactions of alkyl chains. Since on going from the C4 to the C18 reactants the observed rate varies by a factor of two, it is concluded that any of the reactant pairs in the set of compounds examined provide a reasonably good model for the intermolecular analogue of the lactonization reaction.