DFT Studies of Ru-Catalyzed C–O versus C–H Bond Functionalization of Aryl Ethers with Organoboronates

Density functional theory calculations
have been performed to investigate
how different nucleophiles and directing groups affect the preference
of C–H versus C–O bond functionalization in the ruthenium-catalyzed
coupling reactions of aryl ethers with organoboronates. Our results
indicate that the preference depends on the relative stability of
the transition state structures for the C–O bond activation
in the C–O bond functionalization pathway and the transmetalation
with boronate to form a Ru–C bond in the C–H bond functionalization
pathway. When the transition state structure for the transmetalation
with boronate lies lower in energy than that for the C–O bond
activation, C–H bond functionalization is preferred, and vice
versa. How different nucleophiles and directing groups affect the
relative stability of the transition structures has been discussed
in detail.