FeCl3 catalyzed 1,6-conjugate addition of phenol C-nucleophiles: Facile synthesis of diarylmethanes.

An efficient synthesis of diarylmethane derivatives from phenol and a p -quinone methide surrogate cyclohexadienone derivative has been described. This 1,6-conjugate addition reaction is catalyzed by earth abundant FeCl 3 and it proceeds via a consecutive Michael type addition followed by aromatization. Various proportions of phenol and cyclohexadienone produced exclusively mono, bis and tris addition products. Interestingly, di- tert -butylphenol gave addition product with concomitant loss of one of the tertiary butyl groups of the phenol moiety via retro-Friedel-Crafts reaction. This strategy demonstrates a straightforward access to wide range of diarylmethane derivatives possessing biologically significant ortho -methoxyphenol moiety under mild reaction conditions. Image 1 • FeCl 3 Catalyzed synthesis of diarylmethane derivatives from phenol and cyclohexadienone derivative. • In this strategy mono, bis and tris 1,6-conjugate addition products are achieved successfully. • Here we disclosed a novel approach for biologically significant diarylmethane derivatives under mild reaction conditions. • An interesting plausible mechanism has been discussed for diarylmethane derivatives. [ABSTRACT FROM AUTHOR]