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Herein, we develop a metal-free, nondirected, site-selective, one-pot approach to -arylation of arylamines. This Brønsted acid-catalyzed, direct C-C bond formation offers a broad substrate scope and scalability and creates the ideal conditions for overriding the conventional site-selectivity to furnish -substituted anilines. Additionally, the protocol applies to the -allylation of anilines and has been extended to afford late-stage functionalization and synthesis of medicinally privileged arylated diamines and densely functionalized anilines. The control experiments and density functional theory studies provide evidence for the proposed mechanism and selectivity.
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http://dx.doi.org/10.1021/acs.orglett.3c02181 | DOI Listing |
ACS Catal
September 2024
Department of Chemistry, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, California 92037, United States.
Recent advances in ligand design have enabled Pd(II)-catalyzed non-directed C-H functionalization using arenes as the limiting reagent, but achieving catalyst control over the site-selectivity in these transformations remains a significant challenge. Instead, selectivity is typically governed by the inherent steric and electronic properties of the arene substrates or directing effects. Consequently, it can be difficult to selectively functionalize -position of electron-deficient arenes and -positions of electron-rich arenes respectively.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2024
Department of Chemistry, Boston College, Chestnut Hill, MA 02467, USA.
Non-directed regioselective activation of bis(boronic esters), followed by functionalization, is reported. A bulky activator is shown to selectively activate the less hindered boronic ester enabling it to undergo stereospecific cross-coupling to a variety of electrophiles. This steric-based regioselectivity provides a simple and efficient method to prepare highly functionalized, enantiomerically enriched products starting from simple alkenes.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
July 2024
Institut de Química Computacional i Catàlisi (IQCC), Departament de Química, Universitat de Girona, Campus Montilivi, Girona, E-17071, Catalonia, Spain.
The tert-butyl group is a common aliphatic motif extensively employed to implement steric congestion and conformational rigidity in organic and organometallic molecules. Because of the combination of a high bond dissociation energy (~100 kcal mol) and limited accessibility, in the absence of directing groups, neither radical nor organometallic approaches are effective for the chemical modification of tert-butyl C-H bonds. Herein we overcome these limits by employing a highly electrophilic manganese catalyst, [Mn(bpeb)(OTf)], that operates in the strong hydrogen bond donor solvent nonafluoro-tert-butyl alcohol (NFTBA) and catalytically activates hydrogen peroxide to generate a powerful manganese-oxo species that effectively oxidizes tert-butyl C-H bonds.
View Article and Find Full Text PDFOrg Lett
August 2023
Department of Chemistry, Indian Institute of Technology Delhi, New Delhi 110016, India.
Herein, we develop a metal-free, nondirected, site-selective, one-pot approach to -arylation of arylamines. This Brønsted acid-catalyzed, direct C-C bond formation offers a broad substrate scope and scalability and creates the ideal conditions for overriding the conventional site-selectivity to furnish -substituted anilines. Additionally, the protocol applies to the -allylation of anilines and has been extended to afford late-stage functionalization and synthesis of medicinally privileged arylated diamines and densely functionalized anilines.
View Article and Find Full Text PDFOrg Lett
May 2023
Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India.
A Mn(I)-catalyzed site-selective nondirected C3-maleimidation of quinoxaline is established. Herein, the electrophilic C3-metalation precedes over the -directed strategy to access diversely substituted quinoxaline-appended succinimides. The products undergo PIFA-promoted C(sp)-C(sp) spirocyclization via π-electrons drifting from aryls and Selectfluor-mediated dehydrogenation of succinimide at room temperature.
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