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Cationic gold vinyl carbene/allylic cation complexes of the form ( E )-[(L)AuC(H)C(H)CAr 2 ] + OTf − {L = IPr, Ar = Ph [( E )- 5a ], L = IPr, Ar = 4-C 6 H 4 OMe [( E )- 5b ], L = P( t -Bu) 2 o -biphenyl, Ar = 4-C 6 H 4 OMe [( E )- 5c ]} were generated in solution via Lewis acid-mediated ionization of the corresponding gold (γ-methoxy)vinyl complexes ( E )-(L)AuC(H)C(H)C(OMe)Ar 2 at or below −95 °C. Complexes ( E )- 5b and ( E )- 5c were fully characterized in solution employing multinuclear NMR spectroscopy, which established the predominant contribution of the aurated allylic cation resonance structure and the significant distribution of positive charge into the γ-anisyl rings. Complex ( E )- 5b reacted rapidly at −95 °C with neutral two-electron, hydride, and oxygen atom donors exclusively at the C1 position of the vinyl carbene moiety and with p -methoxystyrene to form the corresponding vinylcyclopropane. In the absence of nucleophile ( E )- 5a decomposed predominantly via intermolecular carbene dimerization whereas formation of 1-aryl-5-methoxy indene upon ionization of ( Z )-(IPr)AuC(H)C(H)C(OMe)(4-C 6 H 4 OMe) 2 [( Z )- 6b ] implicated an intramolecular Friedel–Crafts or electrocyclic Nazarov pathway for the decomposition of the unobserved vinyl carbene complex ( Z )-[(IPr)AuC(H)C(H)C(4-C 6 H 4 OMe) 2 ] + OTf − [( Z )- 5b ].
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This content will become publicly available on August 6, 2026
Leveraging Ligand Cooperativity to Accelerate C–H Activation of Alkynes Using a Tris(amido) Zirconium Complex
Early transition metal alkyl and hydride complexes have been widely explored for their propensity to faciltate C–H activation through a concerted σ-bond metathesis mechanism. Herein, we report the synthesis of a tris(amido) Zr(IV) alkyl complex 1 as a precursor of accessing a proposed transient Zr(IV)-hydride. Upon intramolecular C–H activation of a pendent methyl group, a strained cyclometalated complex 2 is obtained. Relief of ring strain and cooperative metal–ligand C–H activation provided access to Zr-acetylide complex 3, which is capable of undergoing insertion reactivity into carbonyl containing compounds, like aldehydes and ketones. Complexes 1–3 are characterized using multinuclear NMR spectroscopy, UV–vis spectroscopy, and X-ray crystallography. Newly reported electron-rich propargylic alcohols 6 and 7 are isolated and fully characterized using multinuclear NMR spectroscopy, ESI-MS, and FTIR.
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- Award ID(s):
- 2237586
- PAR ID:
- 10630497
- Publisher / Repository:
- American Chemical Society
- Date Published:
- Journal Name:
- Organometallics
- Volume:
- 44
- Issue:
- 16
- ISSN:
- 0276-7333
- Page Range / eLocation ID:
- 1744 to 1750
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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