INTRAMOLECULAR DIELS-ALDER REACTION OF VINYLSULFONATES DERIVED FROM HYDROXYALKYL SUBSTITUTED 1,3-DIENES AND OXIDATIVE DESULFURIZATION OF THE RESULTANT SULTONES

Vinylsulfonates prepared from hydroxyalkyl substituted cycloalka-1,3-dienes and acyclic 1,3-dienes by esterification with vinylsulfonyl chloride cycloadd to delta-sultones at temperatures ranging from (OC)-C-. to reflux in toluene. High diastereoselectivity is observed for substrates 2 featuring a cyclic 1,3-diene moiety, whereas a substituent R(2) larger than hydrogen is necessary to achieve good to excellent levels of stereocontrol for substrates 9 possessing an acyclic 1,3-diene unit. Oxidative desulfurization of the resultant sultones via borylation and subsequent peracid treatment yields hydroxy ketones, thus establishing vinylsulfonyl chloride as a regio- and stereoselectively reacting ketene equivalent for the intramolecular Diels-Alder cycloaddition.