KIO4-mediated selective hydroxymethylation /methylenation of imidazo-heteroarenes: a greener approach.

Herein, we report a KIO 4 -mediated, sustainable and chemoselective approach for the one-pot C3( sp 2 )-H bond hydroxymethylation or methylenation of imidazo-heteroarenes with formaldehyde, generated in situ via the oxidative cleavage of ethylene glycol or glycerol (renewable reagents) through the Malaprade reaction. In the presence of ethylene glycol, a series of 3-hydroxymethyl-imidazo-heteroarenes was obtained in good to excellent yields. These compounds are important intermediates to access pharmaceutical drugs, e.g., Zolpidem. Furthermore, by using glycerol, bis(imidazo[1,2- a ]pyridin-3-yl)methane derivatives were selectively obtained in good to excellent yields.