Ir-Catalyzed
ortho-Borylation of Phenols Directed
by Substrate–Ligand Electrostatic Interactions: A Combined
Experimental/in Silico Strategy for Optimizing Weak Interactions
Buddhadeb Chattopadhyay
Jonathan E. Dannatt
Ivonne L. Andujar-De Sanctis
Kristin A. Gore
Robert E. Maleczka
Daniel A. Singleton
Milton R. Smith
10.1021/jacs.7b02232.s001
https://acs.figshare.com/articles/journal_contribution/Ir-Catalyzed_ortho-Borylation_of_Phenols_Directed_by_Substrate_Ligand_Electrostatic_Interactions_A_Combined_Experimental_in_Silico_Strategy_for_Optimizing_Weak_Interactions/5053744
A strategy for affecting ortho versus
meta/para selectivity in
Ir-catalyzed C–H borylations (CHBs) of phenols is described.
From selectivity observations with ArylOBpin (pin = pinacolate), it
is hypothesized that an electrostatic interaction between the partial
negatively charged OBpin group and the partial positively charged
bipyridine ligand of the catalyst favors ortho selectivity. Experimental
and computational studies designed to test this hypothesis support
it. From further computational work a second generation, in silico
designed catalyst emerged, where replacing Bpin with Beg (eg = ethylene
glycolate) was predicted to significantly improve ortho selectivity.
Experimentally, reactions employing B<sub>2</sub>eg<sub>2</sub> gave
ortho selectivities > 99%. Adding triethylamine significantly improved
conversions. This ligand–substrate electrostatic interaction
provides a unique control element for selective C–H functionalization.
2017-04-28 00:00:00
ortho selectivity
CHB
catalyst
ligand
B 2 eg 2
Interaction
Experimental
interaction