Palladium-catalyzed C3-selective C–H oxidative carbonylation of imidazo[1,2-a]pyridines with CO and alcohols: a way to access esters†
A palladium-catalyzed C3-selective C–H oxidative carbonylation for the synthesis of various esters from imidazo[1,2-a]pyridines and CO with high efficiency and high atom economy has been developed. This process features excellent functional-group tolerance and can be safely conducted on a gram scale. This reaction also facilitates the convenient synthesis of clinically used saripidem. Moreover, several natural products such as leaf alcohol, phytol, nerol and tetrahydrogeraniol can be well tolerated, delivering the desired products in good to excellent yields.