Heck vinylations using vinyl sulfide, vinyl sulfoxide, vinyl sulfone, or vinyl sulfonate derivatives and aryl bromides catalyzed by a palladium complex derived from a tetraphosphine

The adverse impact of sulfur compounds on catalytic performance is well known. The tetraphosphine cis,cis,cis-1,2,3,4-tetrakis[(diphenylphosphino)methyl]cyclopentane in combination with allylchloropalladium dimer affords an efficient catalyst for the Heck reaction of sulfur-containing alkenes with aryl bromides. The rates and yields of the reactions strongly depend on the oxidation state of the sulfur atom. Using vinyl sulfides with 1 mol% catalyst, low to moderate yields of arylated alkenes were obtained. Phenyl vinyl sulfoxide was found to be more reactive, and satisfactory yields of (E)-[2-(phenyisulfinyl)vinyl]benzene derivatives were obtained using I mol% catalyst. With methyl vinyl sulfone, very high yields of (E)- [2-(methyl sulfonyl)vinyl] benzene derivatives were obtained using 1-0. 1 mol% catalyst. Phenyl vinyl sulfonie and phenyl vinylsulfonate also gave high yields of the expected products, but in the presence of 0.4-1 mol% catalyst.