Studies on sulfoxide rearrangement: synthesis of dimedone-annelated heterocycles

A number of 3-(4′-aryloxybut-2′-ynyl)thio-5,5-dimethyl cyclohex-2-enones are synthesized in 80–90% yield by phase transfer catalyzed reaction of 5,5-dimethyl-3-merca-ptocyclohex-2-enone with a number of 1-aryloxy-4-chlorobut-2-ynes. The sulfides are oxidized with 1 equiv. of m-chloroperoxybenzoic acid and the resulting sulfoxides are then stirred at r.t. for 6–8 h to give 2-aryloxymethyl-3-(m-chlorobenzoyloxy)-6,6-dimethyl-5,6,7-trihydro benzo(b)thiophene-4-ones in 70–80% yield.