Deprotonative metalation of aromatics using an amino-based lithium cuprate

International audienceA series of chloro- and bromopyridines have been deproto-metalated using a range of 2,2,6,6-tetramethylpiperidino-based mixed lithium-metal combinations. While lithium-zinc and lithium-cadmium bases afforded different mono- and diiodides after subsequent interception with iodine, complete regioselectivities were observed with the corresponding lithium-copper combination, as demonstrated by subsequent trapping with benzoyl chlorides. The obtained selectivities have been discussed in the light of the CH acidities of the substrates, determined both in the gas phase and in THF solution using the DFT B3LYP method