Arenes arylsulfonates

D. Arene Sulfonate-Arylsulfone (Sulfone-Fries) Rearrangement.171... 

C.iv.a. Hydrogenation of Sulfonates. The detachment of substituted arylsulfonates in the presence of a reducing agent such as formic acid provides a traceless cleavage. In this case it is important that the arene core is substituted with electron-withdrawing substituents to enhance the yields significantly (Scheme 45). This approach has been described (without experimental details) quite early in a patent including the possible derivatization of the intermediate o--arylpalladium-aryl complex. " ... 

Several carbon-hydrogen bond substitutions are involved in the palladium-catalysed reaction of arylsulfonic acids with arenes to yield aromatic sulfones. A plausible mechanism, shown in Scheme 9, involves the initial formation of the palladacycle (99) which, after eoupling with the arene, yields the biphenyl derivative (100). Further coordination and carbon-hydrogen activation gives the seven-membered palladacycle (101) that affords the sulfone, (102), after reductive elimination. ... 

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See also in sourсe #XX -- [ , , ]

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