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Stereoretention in styrene heterodimerisation promoted by one-electron oxidants

Zhang, Xinglong and Paton, Robert S. (2020) Stereoretention in styrene heterodimerisation promoted by one-electron oxidants. Chemical Science, 11 (34). pp. 9309-9324. ISSN 2041-6520. https://resolver.caltech.edu/CaltechAUTHORS:20200925-104735099

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Abstract

Radical cations generated from the oxidation of C[double bond, length as m-dash]C π-bonds are synthetically useful reactive intermediates for C–C and C–X bond formation. Radical cation formation, induced by sub-stoichiometric amounts of external oxidant, are important intermediates in the Woodward–Hoffmann thermally disallowed [2 + 2] cycloaddition of electron-rich alkenes. Using density functional theory (DFT), we report the detailed mechanisms underlying the intermolecular heterodimerisation of anethole and β-methylstyrene to give unsymmetrical, tetra-substituted cyclobutanes. Reactions between trans-alkenes favour the all-trans adduct, resulting from a kinetic preference for anti-addition reinforced by reversibility at ambient temperatures since this is also the thermodynamic product; on the other hand, reactions between a trans-alkene and a cis-alkene favour syn-addition, while exocyclic rotation in the acyclic radical cation intermediate is also possible since C–C forming barriers are higher. Computations are consistent with the experimental observation that hexafluoroisopropanol (HFIP) is a better solvent than acetonitrile, in part due to its ability to stabilise the reduced form of the hypervalent iodine initiator by hydrogen bonding, but also through the stabilisation of radical cationic intermediates along the reaction coordinate.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1039/d0sc03059gDOIArticle
ORCID:
AuthorORCID
Zhang, Xinglong0000-0003-1698-692X
Paton, Robert S.0000-0002-0104-4166
Additional Information:This journal is © The Royal Society of Chemistry 2020. Attribution-NonCommercial 3.0 Unported (CC BY-NC 3.0) Received 1st June 2020. Accepted 12th August 2020. Funding from the Agency for Science, Technology and Research (A*STAR), Singapore (X. Z.) is gratefully acknowledged. X. Z. and R. S. P. acknowledge the EPSRC Centre for Doctoral Training in Theory and Modelling in Chemical Sciences (EP/L015722/1) and the use of Dirac cluster. X. Z. thanks Dr Maria Koiyoni for her help with HFIP solvent parametrisation. R. S. P. acknowledges computational resources from the RMACC Summit supercomputer supported by the National Science Foundation (ACI-1532235 and ACI-1532236), the University of Colorado Boulder and Colorado State University, and the Extreme Science and Engineering Discovery Environment (XSEDE) through allocation TG-CHE180056. XSEDE is supported by the National Science Foundation (ACI-1548562). We thank Prof. Aqeel Hussain for sharing information with us. There are no conflicts to declare. All publication charges for this article have been paid for by the Royal Society of Chemistry.
Funders:
Funding AgencyGrant Number
Agency for Science, Technology and Research (A*STAR)UNSPECIFIED
Engineering and Physical Sciences Research Council (EPSRC)EP/L015722/1
NSFACI-1532235
NSFACI-1532236
University of ColoradoUNSPECIFIED
Colorado State UniversityUNSPECIFIED
NSFTG-CHE180056
NSFCHE-1955876
NSFACI-1548562
Royal Society of ChemistryUNSPECIFIED
Issue or Number:34
Record Number:CaltechAUTHORS:20200925-104735099
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200925-104735099
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105557
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:25 Sep 2020 19:35
Last Modified:25 Sep 2020 19:35

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