Salt effect on the endo/exo ratio of the reaction of cyclopentadiene with methyl methacrylate

The salt effect on the stereoselectivity of the reaction of cyclopentadiene with methyl methacrylate has been investigated. CaCl2, Na2SO4, KCl and LiCl enhance the endo/exo ratios, while guanidinium chloride (GnCl) and LiClO4 decrease them. The results are supported by independent calculations of salting-out and in coefficients.