Direct synthesis of N-functionalized indoles through isomerization of azomethine ylides

Synthetic strategies for the construction of C3-N1' bisindoles

C3-N1' bisindoles are unique structures, and the construction of these structures has drawn much attention. However, their synthesis still presents significant challenges that limit the functional group compatibility. This minireview summarizes the recent progress in the methodology for constructing C3-N1' bisindoles. There are two approaches for access to C3-N1' bisindoles: (1) direct approaches including reverse polarity techniques. (2) Stepwise approaches using designed and prefunctionalized substrates enable further functionalization by additional reactions to facilitate access to the target products. I believe that this review will allow its readers to develop novel approaches for the synthesis of C3-N1' bisindoles.