Cobalt-catalyzed stereodivergent semi-hydrogenation of internal alkynes to alkenes is developed. The reaction proceeded through transfer hydrogenation under mild conditions using a base metal CoI2 as the catalyst, and H2O/MeOH as the hydrogen source with Zn as the reductant. The E/Z-selectivity of the product could be switched by changing the solvent and by inclusion/exclusion of a bidentate phosphine ligand (dppe). This method provides a simple and cost effective pathway for the synthesis of 1,2-dideuterioalkenes.
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http://dx.doi.org/10.1039/c9cc01970g | DOI Listing |
Angew Chem Int Ed Engl
November 2024
State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing, 210093, China.
An enzyme-mimicking catalytic system has been established using a singular palladium-based octahedral cage as the supramolecular reactor, deftly unlocking the off-on-off selectivity in the semi-hydrogenation of alkynes. Water serves as a critical regulator, modulating the catalyst states, reaction rates, and endpoints. The choice of solvent system influences the activity of host-guest binding and the reaction types of homogeneous and heterogeneous catalysis, effectively modifying the reaction steps involved in the Z→E isomerization during the semi-hydrogenation of alkynes.
View Article and Find Full Text PDFChemistry
October 2023
Institut de Chimie et Biochimie Moléculaires et Supramoléculaires (ICBMS, UMR 5246 du CNRS), Univ Lyon, Université Lyon 1, 1 rue Victor Grignard, 69100, Villeurbanne, France.
We report a selectivity-switchable nickel hydride-catalyzed methodology that enables the stereocontrolled semi-reduction of internal alkynes to E- or Z-alkenes under very mild conditions. The proposed transfer semi-hydrogenation process involves the use of a dual nickel/photoredox catalytic system and triethylamine, not only as a sacrificial reductant, but also as a source of hydrogen atoms. Mechanistic studies revealed a pathway involving photo-induced generation of nickel hydride, syn-hydronickelation of alkyne, and alkenylnickel isomerization as key steps.
View Article and Find Full Text PDFChem Commun (Camb)
May 2019
YMU-HKBU Joint Laboratory of Traditional Natural Medicine, Yunnan Minzu University, Kunming, 650500, China.
Cobalt-catalyzed stereodivergent semi-hydrogenation of internal alkynes to alkenes is developed. The reaction proceeded through transfer hydrogenation under mild conditions using a base metal CoI2 as the catalyst, and H2O/MeOH as the hydrogen source with Zn as the reductant. The E/Z-selectivity of the product could be switched by changing the solvent and by inclusion/exclusion of a bidentate phosphine ligand (dppe).
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