アンチモン(V)化合物を擬ハロゲン化物として利用したアリールホウ酸類とのBase-freeクロスカップリング反応

抄録

Organoantimony compounds [(Ph₃SbX₂), X=Null, Cl, OAc] have been studied as pseudo-halides in Suzuki-type cross-coupling reaction. It has been found that pentavalent triphenylantimony diacetae with arylboronic acid in the presence of Pd(PPh₃)₄ (5 mol%) in 1,4-dioxane resulted in cross-coupling reaction to give biaryl derivative in good yield (98 %) without any base which is usually used to activate boronic acid in Suzuki-Miyaura coupling with organic halides. This coupling reaction has wide generality and can be applied to a variety of boronic acids, including which bearing a base-sensitive functional group. Various triarylantimony diacetates can also react effectively and gave corresponding biaryls in modest to good yields (69~98 %). The results imply that the acetoxy moiety on antimony plays an important role in accelerating transmetallation of boronic acid in the present reaction.

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