The catalytic one‐bond isomerization (transposition) of 1‐alkenes is an emerging approach to
The relationship
- Award ID(s):
- 2054529
- PAR ID:
- 10538842
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- Chemical Science
- Volume:
- 14
- Issue:
- 47
- ISSN:
- 2041-6520
- Page Range / eLocation ID:
- 13944 to 13950
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Z ‐2‐alkenes. Design of more selective catalysts would benefit from a mechanistic understanding of factors controllingZ selectivity. We propose here a reaction pathway forcis ‐Mo(CO)4(PCy3)(piperidine) (3 ), a precatalyst that shows highZ selectivity for transposition of alpha olefins (e. g., 1‐octene to 2‐octene, 18 : 1Z :E at 74 % conversion). Computational modeling of reaction pathways and isotopic labeling suggests the isomerization takes place via an allyl (1,3‐hydride shift) pathway, where oxidative addition offac ‐(CO)3Mo(PCy3)(η2‐alkene) is followed by hydride migration from one position (cis to allyl C3carbon) to another (cis to allyl C1carbon) via hydride/CO exchanges. Calculated barriers for the hydride migration pathway are lower than explored alternative mechanisms (e. g., change of allyl hapticity, allyl rotation). To our knowledge, this is the first study to propose such a hydride migration in alkene isomerization. -
Abstract N ‐Heterocyclic carbene (NHC) ligands possess the ability to stabilize metal‐based nanomaterials for a broad range of applications. With respect to metal‐hydride nanomaterials, however, carbenes are rare, which is surprising if one considers the importance of metal‐hydride bonds across the chemical sciences. In this study, we introduce a bottom‐up approach that leverages preexisting metal‐metal m‐center‐n‐electron (m c‐n e) bonds to access a highly stable cyclic(alkyl)amino carbene (CAAC) copper‐hydride nanocluster, [(CAAC)6Cu14H12][OTf]2with superior stability compared to Stryker's reagent, a popular commercial phosphine‐based copper hydride catalyst. Density functional theory (DFT) calculations reveal that the enhanced stability stems from hydride‐to‐ligand backbonding with the π‐accepting carbene. This new cluster emerges as an efficient and selective copper‐hydride pre‐catalyst, thereby providing a bench‐stable alternative for catalytic applications. -
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