Proximity as a Component of Organic Reactivity

Article abstract of DOI:10.1021/ja00302a017

Neither the S_N2 reaction of methyl iodide in 100percent pyridine, nor the S_N2 reaction of triethylamine in 100percent ethyl iodide, nor the elimination reaction of 4-(4-nitrophenoxy)-2-butanone in 100percent piperidine displays special reactivity ascribable to the continuous bimolecular contact.It is concluded that proximity, by itself, cannot explain the fast rates characteristic of many intramolecular reactions.Two parameters, time and distance, must be incorporated into the proximity concept to make it viable.