A CHEMICAL, SPECTROSCOPIC, AND THEORETICAL ASSESSMENT OF THE LEWIS ACIDITY OF LICLO4 IN DIETHYL-ETHER

Moderate diastereoselectivity is observed in the reaction of cyclopent adiene with dimethyl maleate and optically active dimenthyl fumarate i n LiClO4/diethyl ether. Moderate regioselectivity is also seen in the reaction of isoprene and methyl acrylate in the same medium. NMR exper iments and MNDO calculations, in conjunction with published work on Li + in the gas phase, demonstrate that the strong, intrinsic Lewis acidi ty of Li+ is moderated in ether by complexation to the solvent and the counterion.