Development and Mechanistic Interrogation of Interrupted Chain-Walking in the Enantioselective Relay Heck Reaction
Overview
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The formation of alkyl-palladium complexes via the nucleopalladation of alkenes is the entry point for a wide range of diverse reactions. One possibility is that the intermediate alkyl-Pd complexes can undergo a "chain-walking" event, to allow for remote functionalization through various termination processes. However, there are few methods to selectively interrupt the chain-walking process at a prescribed location. Herein, we demonstrate that a variety of homoallylic protected amines undergo an interrupted enantioselective relay Heck reaction to give enantioenriched allylic amine products. The selectivity of this process can be diverted to exclusively yield the ene-amide products by virtue of changing the nature of the amine protecting group. To rationalize this observation, we combine experiment and computation to investigate the mechanism of the chain-walking process and termination events. Isotopic labeling experiments and the computed reaction pathways suggest that the system is likely under thermodynamic control, with the selectivity being driven by the relative stability of intermediates encountered during chain-walking. These results illustrate that the chain-walking of alkyl-palladium complexes can be controlled through the alteration of thermodynamic processes and provides a roadmap for exploiting these processes in future reaction development.
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Liu C, Ge R, Chen J, Guo H, Bartholome T, Maiti D Proc Natl Acad Sci U S A. 2024; 121(51):e2408541121.
PMID: 39665763 PMC: 11665887. DOI: 10.1073/pnas.2408541121.
Remote Functionalization by Pd-Catalyzed Isomerization of Alkynyl Alcohols.
Scaringi S, Leforestier B, Mazet C J Am Chem Soc. 2024; 146(27):18606-18615.
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Kissman E, Neugebauer M, Sumida K, Swenson C, Sambold N, Marchand J Proc Natl Acad Sci U S A. 2023; 120(12):e2214512120.
PMID: 36913566 PMC: 10041140. DOI: 10.1073/pnas.2214512120.
Arylazo Sulfones as Nonionic Visible-Light Photoacid Generators.
Di Terlizzi L, Martinelli A, Merli D, Protti S, Fagnoni M J Org Chem. 2022; 88(10):6313-6321.
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Parts-per-million of ruthenium catalyze the selective chain-walking reaction of terminal alkenes.
Sanz-Navarro S, Mon M, Domenech-Carbo A, Greco R, Sanchez-Quesada J, Espinos-Ferri E Nat Commun. 2022; 13(1):2831.
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