Direct use of methanol as an alternative to formaldehyde for the synthesis of 3,3'-bisindolylmethanes (3,3'-BIMs).

Red card for formaldehyde: The direct coupling of indoles with methanol to 3,3'-bisindolylmethanes with good to excellent yields was accomplished by using a commercially available iridium complex. This study demonstrates the potential of direct use of methanol as an alternative to formaldehyde for synthetic transformations.