REGIOCHEMICAL CONTROL OF THE RING-OPENING OF 1,2-EPOXIDES BY MEANS OFCHELATING PROCESSES .10. SYNTHESIS AND RING-OPENING REACTIONS OF MONOFUNCTIONALIZED AND DIFUNCTIONALIZED CIS AND TRANS ALIPHATIC OXIRANE SYSTEMS

The regiochemical outcome of the ring opening of 1,2-epoxides through chelation processes assisted by metal ions, was verified in mono- and difunctionalized aliphatic oxirane systems bearing the heterofunctiona lity (OR) in an homoallylic and/or allylic relationship to the oxirane ring. The effect of the distance of the OR functionality from the oxi rane ring and of the type of protective group on the regiochemical out come of these systems is examined. In some cases, the use of LiClO4 or Mg(ClO4)(2) as the promoting metal salt makes it possible the obtainm ent of a nice regioalternating process.