Synthesis of 2,4‐Diaryl‐1,3‐benzoxazines via FeCl 3 ‐Catalyzed Annulation of ortho ‐Hydroxyphenyl‐Substituted para ‐Quinone Methides with Imidates

A strategy has been established for the synthesis of 2,4‐diaryl‐1,3‐benzoxazines via a FeCl 3 ‐catalyzed annulation of ortho ‐hydroxyphenyl‐substituted para ‐quinone methides ( p ‐QMs) and imidates. This transformation proceeds under mild, operationally‐simple conditions in a very short time. A wide range of substrates was accessed in this facile chemical transformation, in which the cyclized products were isolated in good to excellent yields (37% to 98%). This reaction not only provides an efficient method for the construction of biologically important 2,4‐diaryl‐1,3‐benzoxazines but also greatly enriches the chemistry of p ‐QMs.