We demonstrate the potential of Ni(COD)(DQ), a bench-stable Ni complex, as a catalyst for the reductive coupling of aldehydes with alkynes and ynamides, providing silylated allyl alcohols with excellent yields and regioselectivities. Mass spectrometric identification of the intermediates and DFT studies supported the proposed mechanism.
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http://dx.doi.org/10.1039/d3cc03322h | DOI Listing |
Org Process Res Dev
January 2025
School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, U.K.
We report the development and optimization of a scalable flow process for metallaphotoredox (Ir/Ni) C-O coupling, a mild and efficient approach for forming alkyl-aryl ethers, a common motif in medicinal and process chemistry settings. Time-resolved infrared spectroscopy (TRIR) highlighted the amine as the major quencher of the photocatalyst triplet excited state, along with the formation of an Ir(II) species that, in the presence of the Ni cocatalyst, has its lifetime shortened, suggesting reductive quenching of Ir(III)*, followed by reoxidation facilitated by the Ni cocatalyst. TRIR and batch reaction screening was used to develop conditions transferrable to flow, and many processing benefits of performing the reaction in flow were then demonstrated using a simple to construct/operate, small-footprint FEP coil flow reactor, including short (<10 min) space times and reduced catalyst loadings (down to 0.
View Article and Find Full Text PDFFront Microbiol
January 2025
College of Grassland Science, Xinjiang Agricultural University, Urumqi, China.
Iron (Fe) minerals possess a huge specific surface area and high adsorption affinity, usually considered as "rust tanks" of organic carbon (OC), playing an important role in global carbon storage. Microorganisms can change the chemical form of Fe by producing Fe-chelating agents such as side chains and form a stable complex with Fe(III), which makes it easier for microorganisms to use. However, in seasonal frozen soil thawing, the succession of soil Fe-cycling microbial communities and their coupling relationship with Fe oxides and Fe-bound organic carbon (Fe-OC) remains unclear.
View Article and Find Full Text PDFNat Chem
January 2025
Instituto de Investigaciones Químicas, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Sevilla, Spain.
Open-shell systems based on first-row transition metals and their involvement in various catalytic processes are well explored. By comparison, mononuclear open-shell complexes of precious transition metals remain underdeveloped. This is particularly true for Ir complexes, as there is very limited information available regarding their application in catalysis.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Sichuan University, West China School of Pharmacy, Renmin Sout Road, 3rd Section, 17#, 610041, Chengdu, CHINA.
Bryostatins are a family of marine natural products that have garnered significant interests, as evidenced by over 40 clinical trials. However, their extremely low natural abundance has severely limited further research. Despite significant efforts, which have led to the total synthesis of seven bryostatin members by eight independent research groups, these complex molecules present persistent challenges for stereocontrolled, large-scale, and especially divergent synthesis.
View Article and Find Full Text PDFChem Sci
January 2025
State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry College of Chemistry and Chemical Engineering, Xiamen University Xiamen 361005 China
Lytic polysaccharide monooxygenases (LPMOs) are a unique group of monocopper enzymes that exhibit remarkable ability to catalyze the oxidative cleavage of recalcitrant carbohydrate substrates, such as cellulose and chitin, by utilizing O or HO as the oxygen source. One of the key challenges in understanding the catalytic mechanism of LPMOs lies in deciphering how they activate dioxygen using diverse reductants. To shed light on this intricate process, we conducted in-depth investigations using quantum mechanical/molecular mechanical (QM/MM) metadynamics simulations, molecular dynamics (MD) simulations, and density functional theory (DFT) calculations.
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