Stereochemistry of the hydrogen–deuterium base-catalysed exchange and conformation of cyclic five-membered sulphonium cations
Abstract
Nuclear Overhauser experiments indicate that the ring protons of cation (1a) which undergo fast base-catalysed exchange are cis to S–Me; values of Jgem for conformationally rigid thiolanium cations suggest a half-chair conformation for (I).