A novel one-pot iridium-catalyzed domino hydroxymethylation of olefins, which relies on using two different ligands at the same time, is reported. DFT computation reveals different activities for the individual hydroformylation and hydrogenation steps in the presence of mono- and bidentate ligands. Whereas bidentate ligands have higher hydrogenation activity, monodentate ligands show higher hydroformylation activity. Accordingly, a catalyst system is introduced that uses dual ligands in the whole domino process. Control experiments show that the overall selectivity is kinetically controlled. Both computation and experiment explain the function of the two optimized ligands during the domino process.
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http://dx.doi.org/10.1002/chem.202104012 | DOI Listing |
Chemistry
February 2022
Leibniz-Institut für Katalyse e.V., Albert-Einstein-Straße 29a, 18059, Rostock, Germany.
A novel one-pot iridium-catalyzed domino hydroxymethylation of olefins, which relies on using two different ligands at the same time, is reported. DFT computation reveals different activities for the individual hydroformylation and hydrogenation steps in the presence of mono- and bidentate ligands. Whereas bidentate ligands have higher hydrogenation activity, monodentate ligands show higher hydroformylation activity.
View Article and Find Full Text PDFOrg Lett
December 2017
Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, P. R. China.
A useful synthesis of five-membered N-heterocycles has been developed through an iridium-catalyzed domino-ring-opening cyclization of vinylaziridines with β-ketocarbonyls. α-Substituted 1,3-dicarbonyls reacted with vinylaziridines to give 2-methylenepyrrolidines bearing two adjacent sp-carbon centers with moderate to excellent diastereoselectivity, while the reaction of α-unsubstituted 1,3-dicarbonyls afforded 2-pyrrolines in good yield.
View Article and Find Full Text PDFChemistry
March 2017
Leibniz-Institut für Katalyse e.V. an der, Universität Rostock, Albert-Einstein-Straße 29a, 18059, Rostock, Germany.
Flavones are important natural products with diverse biological activities. In this study, a novel procedure for the carbonylative synthesis of flavones has been developed by using simple phenols and internal alkynes as the substrates. Various flavones were isolated in moderate to good yields with excellent regioselectivity and functional group tolerance by using an iridium catalyst system.
View Article and Find Full Text PDFChemistry
January 2015
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA (UK).
A new chemoselective reductive nitro-Mannich cyclization reaction sequence of nitroalkyl-tethered lactams has been developed. Relying on the rapid and chemoselective iridium(I)-catalyzed reduction of lactams to the corresponding enamine, subsequent nitro-Mannich cyclization of tethered nitroalkyl functionality provides direct access to important alkaloid natural-product-like structures in yields up to 81 % and in diastereoselectivities that are typically good to excellent. An in-depth understanding of the reaction mechanism has been gained through NMR studies and characterization of reaction intermediates.
View Article and Find Full Text PDFJ Am Chem Soc
November 2011
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China.
An Ir-catalyzed allylic vinylation reaction of allyl carbonates with o-aminostyrene derivatives has been realized, providing skipped (Z,E)-diene derivatives. With (E)-but-2-ene-1,4-diyl dimethyl dicarbonate as the substrate, an efficient enantioselective synthesis of 1-benzazepine derivatives via an Ir-catalyzed domino allylic vinylation/intramolecular allylic amination reaction has been developed. Mechanistic studies of the allylic vinylation reaction have been carried out, and the results suggest that the leaving group of the allylic precursor plays a key role in directing the reaction pathway.
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