Predictable and site-selective functionalization of poly(hetero)arene compounds by palladium catalysis.
The challenge of achieving selective and predictable functionalizations at C-H bonds with complex poly(hetero)aromatic substrates was addressed by two different approaches. Site-selectivity can be obtained by applying various reaction conditions that are (hetero)arene specific to substrates that contain indoles, pyridine N-oxide, and polyfluorinated benzenes. An experimental classification of electron-rich heteroarenes based on their reactivity toward palladium-catalyzed C-H functionalization was established, the result of which correlated well with the order of reactivity predicted by the DFT-calculated concerted metalation-deprotonation (CMD) pathway. Model substrates containing two reactive heteroarenes were then reacted under general reaction conditions to demonstrate the applicability this reactivity chart in predicting the regioselectivity of the palladium-catalyzed direct arylation and benzylation reactions.
Center for Catalysis Research and Innovation, Department of Chemistry, University of Ottawa, ON, Canada. dlapo063@uottawa.ca
David
D
Lapointe
Thomas
T
Markiewicz
Christopher J
CJ
Whipp
Amy
A
Toderian
Keith
K
Fagnou
D006571:Heterocyclic Compounds / Q000737:chemistry*; D006845:Hydrocarbons, Fluorinated / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D013237:Stereoisomerism
D006571:Heterocyclic Compounds; D006845:Hydrocarbons, Fluorinated; D009942:Organometallic Compounds; D010165:Palladium