Radical β-addition to acyclic α-(arylsulfinyl) enones: Pummerer-type rearrangement

The reaction of (S,E)-3-(p-tolylsulfinyl)pent-3-en-2-one with an isopropyl radical, generated from isopropyl iodide and triethylborane, gives the non-stereoselective addition product and an unexpected α-(arylsulfanyl) enone which is formed through a radical addition and subsequent Pummerer-type rearrangement. The formation of the α-(arylsulfanyl) enone depends upon the additives used as well as the aryl group on the sulfur.