Catalytic Hypervalent Iodine Promoters Lead to Styrene Dimerization and the Formation of Tri- and Tetrasubstituted Cyclobutanes

Reported herein is that the use of catalytic quantities of hypervalent iodine reagents (phenyliodine diacetate or Dess-Martin periodinane) allows the rapid and stereoselective formation of cyclobutanes under very mild reaction conditions. The presence of a fluorinated solvent is essential for the success of these reactions which form unsymmetrical tri- and tetrasubstituted cyclobutanes through a heterodimerization process involving two different alkenes.