Quantitative Reactivity Models for Oxidative Addition to L 2 Pd(0): Additional Substrate Classes, Solvents, and Mechanistic Insights.

Autor: Lu J; Department of Chemistry, University of Victoria, 3800 Finnerty Rd., Victoria, BC V8P 5C2, Canada., Celuszak H; Department of Chemistry, University of Victoria, 3800 Finnerty Rd., Victoria, BC V8P 5C2, Canada., Paci I; Department of Chemistry, University of Victoria, 3800 Finnerty Rd., Victoria, BC V8P 5C2, Canada., Leitch DC; Department of Chemistry, University of Victoria, 3800 Finnerty Rd., Victoria, BC V8P 5C2, Canada.
Jazyk: angličtina
Zdroj: Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2024 Nov 07; Vol. 30 (62), pp. e202402282. Date of Electronic Publication: 2024 Oct 14.
DOI: 10.1002/chem.202402282
Abstrakt: Quantitative molecular structure-reactivity models are useful for generating predictions to guide synthesis design, and in formulating and testing mechanistic hypotheses. We report an expanded multivariate linear regression (MLR) model for the rate of (hetero)aryl (pseudo)halide oxidative addition to L 2 Pd(0), here exemplified by Pd(PCy 3 ) 2 . This builds on a prior model from our group, with additional substrate classes (aryl chlorides and iodides) and reaction solvents (THF, toluene, THF/DMF mixture). Overall solvent effects across the entire substrate set are minimal under these conditions, enabling a unified MLR model without introduction of new molecular descriptors beyond the original five. Examining the mechanistic origin of the two molecular electrostatic potential (ESP) descriptors led to generation of a simpler, four descriptor model that is suitable for aryl halides, but not for 2-halopyridines. Using this model we identified a mechanistic outlier, 2-pyridyl triflate, which undergoes a nucleophilic displacement oxidative addition that does not involve the adjacent nitrogen atom. Finally, we discuss the relationship between C-X bond strength and oxidative addition rates, and compare the intrinsic bond strength index (IBSI) to bond dissociation enthalpy (BDE) as a bond strength descriptor.
(© 2024 The Author(s). Chemistry - A European Journal published by Wiley-VCH GmbH.)
Databáze: MEDLINE
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