Iridium-catalyzed
C–H borylation of CF
3
-substituted
pyridines is described in this paper. The boronic ester group can
be installed on the α, β, or γ position of pyridine
by an appropriate substitution pattern. Sterically governed regioselectivity
provides convenient access to a variety of CF
3
-substituted
pyridylboronic esters. These catalytic C–H borylation reactions
were carried out neatly without the use of any solvent. Several functional
groups, such as halo, ester, alkoxy, amino, etc., are compatible with
this methodology. These pyridylboronic esters are amenable to column
chromatography and the products were isolated in good to excellent
yields. α-Borylated pyridines, although isolated in good yields,
do not have a long shelf life. The boronic ester derivatives of these
CF
3
-substituted pyridines can serve as useful precursors
in the synthesis regime.
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