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Parahydrogen‐Induced Polarization in Hydrogenation Reactions Mediated by a Metal‐Free Catalyst

We report nuclear spin hyperpolarization of various alkenes achieved in alkyne hydrogenations with parahydrogen over a metal‐free hydroborane catalyst (HCAT). Being an intramolecular frustrated Lewis pair aminoborane, HCAT utilizes a non‐pairwise mechanism of H(2) transfer to alkynes that normally p...

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Detalles Bibliográficos
Autores principales: Zakharov, Danila O., Chernichenko, Konstantin, Sorochkina, Kristina, Yang, Shengjun, Telkki, Ville‐Veikko, Repo, Timo, Zhivonitko, Vladimir V.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9303582/
https://www.ncbi.nlm.nih.gov/pubmed/34928532
http://dx.doi.org/10.1002/chem.202103501
Descripción
Sumario:We report nuclear spin hyperpolarization of various alkenes achieved in alkyne hydrogenations with parahydrogen over a metal‐free hydroborane catalyst (HCAT). Being an intramolecular frustrated Lewis pair aminoborane, HCAT utilizes a non‐pairwise mechanism of H(2) transfer to alkynes that normally prevents parahydrogen‐induced polarization (PHIP) from being observed. Nevertheless, the specific spin dynamics in catalytic intermediates leads to the hyperpolarization of predominantly one hydrogen in alkene. PHIP enabled the detection of important HCAT‐alkyne‐H(2) intermediates through substantial (1)H, (11)B and (15)N signal enhancement and allowed advanced characterization of the catalytic process.