Mechanistic Studies for Synthesis of Bis(indolyl)methanes: Pd-Catalyzed C–H Activation of Indole–Carboxylic Acids with Benzyl Alcohols in Water
نویسندگان
چکیده
A method for synthesis without protecting groups of bis(indolyl)methanes by the (η-benzyl)palladium system generated from a palladium catalyst and benzyl alcohol in water is developed. This domino protocol involves C3–H bond activation/benzylation of indole–carboxylic acids and benzylic C–H functionalization. Mechanistic studies indicate that the (η-benzyl)palladium(II) complex, which is formed via oxidative addition of benzyl alcohol 2 to a Pd(0) species, activates the C–H bond at the C3-position of indole 1. Notably, water plays an important role in our catalytic system for sp C–O bond activation and stabilization of OH by hydration for the smooth generation of the activated Pd(II) cation species, as well as for nucleophilic attack of indoles to hydrated benzyl alcohols.
منابع مشابه
An efficient green procedure for the synthesis of bis (indolyl) methanes in water
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