Methylene Surrogates for the Synthesis of 3,3’‐Diindolylmethanes

Abstract Di(1 H ‐indol‐3‐yl)methanes (DIMs) and their derivatives are one of the highly essential indole derivatives with a broad spectrum of biological activities. The scaffold involves two indole/substituted indole moieties connected to each other via a methenyl bridge generally at the 3,3’ positions, as well as 2,2’ and 2,3’ positions. Synthesis of such moieties with the use of easily available chemicals and process is highly desirable for its tremendous importance in the fields of organic and medicinal chemistry. Herein, we review the synthesis of 3,3’‐methylene bridged indoles with the use of some methylene surrogates under various chemical and catalytic conditions.