Direct dilithiation of N-aryl heterocycles for the construction of condensed N-heterocycles

Abstract

A 1,4-dilithio intermediate can be prepared from N-heterocycles by n-BuLi-promoted direct C–H dilithiation. The subsequent trapping of the 1,4-dilithio intermediate with acyl chlorides affords condensed N-heterocycles in high yields in a one-pot fashion. This protocol features a broad substrate scope, good efficiency, and high atom economy. The control experiments support the presence of a 1,4-dilithio intermediate.