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Abstract Intermediates relevant to cobalt‐catalyzed alkene hydroformylation have been isolated and evaluated in fundamental organometallic transformations relevant to aldehyde formation. The 18‐electron (R,R)‐(iPrDuPhos)Co(CO)2H has been structurally characterized, and it promotes exclusive hydrogenation of styrene in the presence of 50 bar of H2/CO gas (1:1) at 100 °C. Deuterium‐labeling studies established reversible 2,1‐insertion of styrene into the Co−D bond of (R,R)‐(iPrDuPhos)Co(CO)2D. Whereas rapid β‐hydrogen elimination from cobalt alkyls occurred under an N2atmosphere, alkylation of (R,R)‐(iPrDuPhos)Co(CO)2Cl in the presence of CO enabled the interception of (R,R)‐(iPrDuPhos)Co(CO)2C(O)CH2CH2Ph, which upon hydrogenolysis under 4 atm H2produced the corresponding aldehyde and cobalt hydride, demonstrating the feasibility of elementary steps in hydroformylation. Both the hydride and chloride derivatives, (X=H−, Cl−), underwent exchange with free13CO. Under reduced pressure, (R,R)‐(iPrDuPhos)Co(CO)2Cl underwent CO dissociation to form (R,R)‐(iPrDuPhos)Co(CO)Cl.
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Excited‐State Copper Catalysis for the Synthesis of Heterocycles
Abstract Heterocycles are one of the largest groups of organic moieties with significant medicinal, chemical, and industrial applications. Herein, we report the discovery and development of visible‐light‐induced, synergistic excited‐state copper catalysis using a combination of Cu(IPr)I as a catalyst andrac‐BINAP as a ligand, which produces more than 10 distinct classes of heterocycles. The reaction tolerates a broad array of functional groups and complex molecular scaffolds, including derivatives of peptides, natural products, and marketed drugs. Preliminary mechanistic investigation suggests in situ generations of [Cu(BINAP)2]+and [Cu(IPr)2]+catalysts that work cooperatively under visible‐light irradiation to facilitate catalytic carbo‐aroylation of unactivated alkenes, affording a wide range of useful heterocycles.
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- Award ID(s):
- 1848463
- PAR ID:
- 10363172
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 61
- Issue:
- 4
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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