Iron-catalyzed
C–H functionalization of aromatics has attracted
widespread attention from chemists in recent years, while the requirement
of an elaborate directing group on the substrate has so far hampered
the use of simple aromatic carbonyl compounds such as benzoic acid
and ketones, much reducing its synthetic utility. We describe here
a combination of a mildly reactive methylaluminum reagent and a new
tridentate phosphine ligand for metal catalysis, 4-(bis(2-(diphenylphosphanyl)phenyl)phosphanyl)-<i>N</i>,<i>N</i>-dimethylaniline (Me<sub>2</sub>N-TP), that allows us to convert an <i>ortho</i> C–H
bond to a C–CH<sub>3</sub> bond in aromatics and heteroaromatics
bearing simple carbonyl groups under mild oxidative conditions. The
reaction is powerful enough to methylate all four <i>ortho</i> C–H bonds in benzophenone. The reaction tolerates a variety
of functional groups, such as boronic ester, halide, sulfide, heterocycles,
and enolizable ketones
