Selective Organocatalytic Synthesis of 3‐Methylindoles and Diindolylmethanes Through Reductive Methylation of Indoles with CO2

The direct reductive methylation of indoles with CO₂ remains a formidable challenge due to competing reduction pathways and precise selectivity control. Herein, we disclose cooperative catalytic systems comprising 2‐aminopyridine‐BH3 and DIC‐BH3 that enable unprecedented chemoselective C3‐methylation of indoles under mild conditions (1 atm CO2). This strategy delivers two distinct product classes through controlled reduction: 3‐methylindoles (up to 81% yield) and diindolylmethanes (up to 82% yield) with excellent functional group tolerance. This protocol offers novel synthetic routes for the synthesis of indole‐based bioactive molecules.