The research on alternative media for organic transformations remains a highly demanding topic. In this paper, we describe a sustainable, microwave‐enhanced approach to 2‐substitued benzofurans starting from substituted o ‐alkynylanisoles. The method involves the use of an acidic deep eutectic solvent that acts simultaneously as reaction medium and catalyst. The optimized reaction conditions are quite mild (100°C) and the process is complete within 3 h. The reaction setup is simple and does not require an inert atmosphere. Under these conditions, seventeen benzofurans were synthesized in yields of up to 90%. A plausible reaction mechanism has been proposed and supported by headspace GC analyses. To evaluate the sustainability of the process Sheldon's simple environmental factor was also calculated.
Gritti et al. (Mon,) studied this question.