During the past 15 years, studies on the Diels-Alder reaction'have produced dramatic results. The pronounced rate enhancements and improved stereoselectivities observed to date have been associated with cycloadditions conducted in (1) aqueous media2 and (2) conventional organic solvents under ultrahigh pressure (8-20 kbar). 3 While seemingly the result of two independent physical processes, it is mast likely that there is a direct ...
