98%
921
2 minutes
20
We report iridium-catalyzed C-H borylations for the regioselective synthesis of distally disubstituted calix[4]arene macrocycles. The atom- and step-economical method led to a broad family of calix[4]arenes in good yields and functional group tolerance. The synthetic utility of the C-H borylation protocol was finally illustrated with several late-stage modifications for the synthesis of elaborate calix[4]arenes frameworks, otherwise challenging to achieve with commonly employed procedures.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/acs.joc.4c00419 | DOI Listing |
J Am Chem Soc
August 2025
Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
Bipolarolides A and B are members of the ophiobolin family of sesterterpenes, characterized by their intricate cage-like structures. Herein we report a concise asymmetric total synthesis of bipolarolides A and B enabled by the type-II Diels-Alder reaction. The synthesis features a sequence of key transformations: an iridium-catalyzed enantioselective allylation to establish the first stereocenter, type-II Diels-Alder reaction to rapidly assemble the bicyclo[3.
View Article and Find Full Text PDFJ Am Chem Soc
July 2025
Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States.
Aldehyde α-alkylation remains a challenging transformation. On the other hand, given the wide availability of alkenes, it has been an attractive objective to use unactivated alkenes as alkylating agents. Here, as an initial model study, we report a stepwise asymmetric α-alkylation of aldehydes with simple alkenes as the coupling partner.
View Article and Find Full Text PDFJ Org Chem
June 2025
Centre for Hyperpolarisation in Magnetic Resonance, University of York, Heslington YO10 5NY, U.K.
Hydrogen isotope exchange (HIE) of -heterocycles is highly important in synthesis, where it is often used to prepare probes suitable for pharmaceutical studies. In this work, we show that pharmaceuticals such as anastrozole, trimethoprim, and bisacodyl can be easily deuterated in up to 84-95%, with high site selectivity using an [IrCl(COD)(IMes)]/H/NaOMe/methanol- derived catalytic system. We studied in detail the deuteration of quinoxaline using NMR spectroscopy, mass spectrometry, and X-ray crystallography and characterized a range of C-H bond activated products that include [Ir(H)(quinoxaline)(IMes)(κ-μ-C,N-quinoaxline)Ir(H)(quinoxaline)(IMes)]; [Ir(H)(quinoxaline)(IMes)(κ-μ-C,N-quinoxaline)Ir(Cl)(H)(quinoxaline)(IMes)]; [Ir(H)(IMes)(κ-μ-C,N-quinoxaline)Ir(H)(IMes)]; and [Ir(H)(IMes)(κ-μ-C,N-quinoxaline)(μ-H)Ir(H)(quinoxaline)(IMes)].
View Article and Find Full Text PDFACS Catal
May 2025
Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica. Universidade de Santiago de Compostela, Santiago de Compostela 15782, Spain.
Bipyridine and phenanthroline are well-established neutral ligands for promoting iridium-catalyzed borylations of aromatic C-H bonds. However, their use with aliphatic substrates is almost uncharted. Herein we demonstrate that introducing CF substituents at the 5- and 5'-positions of bipyridine generates ligands that enable an efficient and regioselective iridium-catalyzed borylation of the methyl group in a broad variety of methylamides.
View Article and Find Full Text PDFJ Am Chem Soc
June 2025
State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.
In modern organic chemistry, 1,2-hydride shifts of carbocations are generally considered to be highly rapid processes, typically exhibiting activation barriers of ∼2-4 kcal/mol─significantly faster than conventional S1 or E1 reactions. Consequently, achieving a catalytic enantioselective 1,2-hydride shift remains a significant challenge. Herein, we introduce a nitrene-mediated strategy that generates carbocation intermediates through intramolecular metal-nitrenoid transfer to alkenes, followed by a ligand-enabled, stereocontrolled, and accelerated 1,2-hydride shift facilitated by attractive noncovalent interactions.
View Article and Find Full Text PDF