TFA-catalyzed C-N bond activation of enamides with indoles: efficient synthesis of 3,3-bisindolylpropanoates and other bisindolylalkanes

An efficient TFA-catalyzed cleavage of C-N bonds in alkylation of indoles by tertiary enamides was described. A variety of bisindolylalkane derivatives, especially 3,3-bisindolylpropanoates, were expeditiously synthesized in good yields.