Enantioselective synthesis of triarylmethanes via organocatalytic transfer hydrogenation of para -quinone methides.

A new organocatalytic asymmetric method for the synthesis of enantioenriched triarylmethanes is developed. Different from the conventional approaches featuring asymmetric arylation, the present study employs asymmetric reduction via C-H bond formation as the key step. This approach does not require the presence of a heteroaryl ring or the presynthesis of unstable para -quinone methides. Instead, the stable racemic triarylmethanols were used as substrates for the in situ generation of the intermediates with a suitable chiral phosphoric acid catalyst.