O -Tetrahydropyran-2-yloxy ( O -THP) as an ortho -Directing Group in the Lithiation of Pyridines

International audienceHerein we report regioselective deprotonations of 3- and 4-(tetrahydropyran-2-yloxy)pyridine with n-butyllithium. Trapping the lithiated species with various electrophiles afforded functionalized pyridines in good yields. A one-pot procedure also allowed the double functionalization at C4 and C2 in the case of 3-O-THP-pyridine. The ortho-metallating ability of this group was examined in comparison with other well-known oxygen-based ortho-directing groups