Intramolecular Interactions between a Group Bearing n-Electrons and a CH2–X Where X is an Electronegative Group

Abstract

Abstract Conformational equilibrium of 9-(2-acyloxyethyl)-1,4-dimethoxytriptycenes in chloroform-d suggests that the stability of the ±sc conformation increases as the electronegativity of the acyl group increases. The results together with other pertinent data are discussed from the stand point that there is an attractive interaction between the acyloxymethyl and the methoxyl groups in proximity. Reflecting its high ionization potential, the chloro group in 1-position showed no stabilization of the ±sc conformation, although mass spectra and some chemical properties indicate that there is an interaction between the chloro group and highly electronegative CH2X group. A possible correlation of these results with the incipient transition state for SN2 reactions is suggested.