Visible Light-Mediated Preparation of a Key Intermediate Employed in the Synthesis of Zolpidem and Several Analogs

This work describes a protocol being only promoted by visible light for the C3-alkylation of imidazo[1,2-a]pyrimidines and imidazo[1,2-a]pyridines with aryldiazoacetates. Several known and new analogs of a key intermediate employed in previous syntheses of zolpidem have been accessed in good yields. The preparation of this key intermediate was also achieved using this method, but an adjustment of the nature of the alkylating agent was required.