F. J. Leeper and D. H. C. Smith
"The Effect of Strain on the Catalytic Reactions of Bridged Thiazolium Salts as Models of Thiamin"
J. Chem. Soc., Chem. Commun.,1990, 961-963. Full Text
The reactivity of bridged thiazolium salts (9) and (10) has been studied; the model (9) with the shorter bridge is unable to catalyse the benzoin condensation reaction and it was shown that this is due to failure of the condensation step (5) -> (6), probably owing to the effects of strain.
Department of Chemistry
University of Cambridge