A New Homogeneous Catalyst for the Synthesis of 3,3′‐bis(indolyl)methanes (BIMs): Collective Synthesis of Arundine, Turbomycin B, Arsindoline A and Tris(1H‐indol‐3‐yl)methane*

Abstract

An environmentally friendly, cost‐effective, and efficient method for synthesizing 3,3′‐bis(indolyl)methanes (BIMs) and their derivatives was developed through an electrophilic substitution reaction of indole with various aldehydes. This reaction was catalyzed by DABCO(TfOH)₂ a homogeneous catalyst with HFIP serving as solvent. The process, performed exclusively in DABCO(TfOH)₂, demonstrated excellent catalytic activity, yielding high product amounts (84‐98%) and showing broad functional group compatibility, which enabled the efficient synthesis of both natural alkaloids and BIM derivatives. Interstingly, we successfully synthesized the natural alkaloids to enhance the diversity of the compound library. mechanistic studies highlight a delicate balance between fluorinated solvent, catalyst and sunstrate as essential for achieving nature’s approach to selective cyclization in organic synthesis.