This document does not have an outline. ... JavaScript is disabled on your browser. Please enable JavaScript to use all the features on this page. ... Author links open the overlay panel. Numbers correspond to the affiliation list which can be exposed by using the show more link. ... Steric acceleration by α-substituents in pyridine leaving groups is quantitatively assessed. Constraint of α-phenyls to near planarity forms superior leaving groups for S N 2 displacements. α-t- ...