Synthesis of 11H-Benzo[b]Fluoren-11-One via an Unprecedented Cascade Reaction of O-Phthaladehyde

Abstract

Developing multicomponent reactions in a cascade manner is a long-standing interest to chemists to access valuable organic materials more economically. Herein, we described a simple, economically viable method for synthesizing 11H-benzo[b]fluoren-11-one, a dual-state organic fluorophore, starting from ortho phthalaldehyde (OPA) in DMSO solvent. Simple and rapid product isolation, high atom economy, short reaction time, and scalability are the attractive features of the method. During the optimization of the reaction condition, we observed that DMSO, DMF, and acetone served one carbon to form the said compound besides their role as solvents. A plausible mechanism has been proposed based on the evidence obtained from LCMS analysis of the incomplete reaction mixture.