Summary. The inference of single bicyclic intermediates in t h e competition of diglymc (or triglyme) 1) with tetrahydrofurfuryl alcohol is confirmed by analysis of the linewidths. The dissymetric bicyclic species are characterized by linewidths increased markcdly with respect to the pure solvents, without an acisompanying change in the 23Na chemical shift. Conversely, the competition of glyme with the same alcohol involves three equi-probable intermediates; that of tetrahydrofuran (or tetrahydropyran) is of greatcr conceptual complexity.