A Tandem Madelung Indole Synthesis Mediated by a LiN(SiMe)/CsF System.

A tandem Madelung indole synthesis by the reaction of methyl benzoate and -methyl--toluidine has been discovered. The combination of LiN(SiMe) with CsF is the key factor, which secures the high efficiency of such tandem transformations. Simply combining methyl benzoate, -methyl--toluidine LiN(SiMe), and CsF generated a diverse array of -methyl-2-phenylindoles (31 examples, 50-90% yields). Furthermore, the scalability and the poststructural modifications of this indole synthesis were demonstrated.