A Tandem Madelung Indole Synthesis Mediated by a LiN(SiMe 3 ) 2 /CsF System.

A tandem Madelung indole synthesis by the reaction of methyl benzoate and N -methyl- o -toluidine has been discovered. The combination of LiN(SiMe 3 ) 2 with CsF is the key factor, which secures the high efficiency of such tandem transformations. Simply combining methyl benzoate, N -methyl- o -toluidine LiN(SiMe 3 ) 2 , and CsF generated a diverse array of N -methyl-2-phenylindoles (31 examples, 50-90% yields). Furthermore, the scalability and the poststructural modifications of this indole synthesis were demonstrated.