Acceleration of the intramolecular Diels-Alder reaction of vinylsulfonic esters and amides bearing acyclic and carbocyclic 1,3-diene moieties by application of high pressure leads to excellent yields of sultones and sultams, respectively, at ambient temperature. The influence of pressure on the stereoselectivity of these processes has been investigated. (C) 2000 Elsevier Science Ltd.