Metal-Free Synthesis of Trifluoromethyl Carbinol-Containing Imidazo[1,2-a ]pyridines via Dehydrative Coupling of Imidazo[1,2-a ]pyridines with Trifluoroacetaldehyde

A facile and efficient method for the synthesis of trifluoro-methylated carbinols has been developed from imidazo[1,2-a]pyridinesand trifluoroacetaldehyde. The direct C(sp(2))-H hydroxytrifluoromethyl-ation is successfully implemented at room temperature using HFIP assolvent through dehydrative cross-coupling process, which displays abroad substrate scope and functional group tolerance. Furthermore,gram-scale and synthetic transformation experiments have also beendemonstrated, which indicate its potential applicable values in organicsynthesis. This green protocol features operational simplicity, atomeconomy, mild reaction conditions (e.g., at room temperature, transi-tion-metal- and oxidant-free, without inert gas protection), wide sub-strate scope, and excellent practicality.