High Pressure Organometallic Chemistry : Diastereoselectivity in Diels Alder Reactions of 2,3-Dimethyl-1,3-Butadiene with (Z)-3-Tributyl-Stannylacrylic Acid (-) Menthyl Ester

摘要

The effect of pressure (0.1 to 25OO MPa) on the asymmetric induction in the cycloaddition between (-)-menthyl 3-tributylstannyl-acrylate and 2,3-dimethyl-1,3-butadiene has been investigated under different solvent and temperature conditions. The high pressure considerably facilitates the addition but leads to a decrease or even an inversion of the diastereomeric excess. This behavior can be explained by a favored cisoid conformation of the ethylenic ester under high pressure.