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Abstract A metal/ligand cooperative approach to the reduction of small molecules by metal silylene complexes (R2Si=M) is demonstrated, whereby silicon activates the incoming substrate and mediates net two‐electron transformations by one‐electron redox processes at two metal centers. An appropriately tuned cationic pincer cobalt(I) complex, featuring a central silylene donor, reacts with CO2to afford a bimetallic siloxane, featuring two CoIIcenters, with liberation of CO; reaction of the silylene complex with ethylene yields a similar bimetallic product with an ethylene bridge. Experimental and computational studies suggest a plausible mechanism proceeding by [2+2] cycloaddition to the silylene complex, which is quite sensitive to the steric environment. The CoII/CoIIproducts are reactive to oxidation and reduction. Taken together, these findings demonstrate a strategy for metal/ligand cooperative small‐molecule activation that is well‐suited to 3dmetals.
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Cobalt‐Catalyzed Decarboxylative Allylations: Development and Mechanistic Studies
Abstract In recent years, there has been a concerted drive to develop methods that are greener and more sustainable. Being an earth‐abundant transition metal, cobalt offers an attractive substitute for commonly employed precious metal catalysts, though reactions engaging cobalt are still less developed. Herein, we report a method to achieve the decarboxylative allylation of nitrophenyl alkanes, nitroalkanes, and ketones employing cobalt. The reaction allows for the formation of various substituted allylated products in moderate‐excellent yields with a broad scope. Additionally, the synthetic potential of the methodology is demonstrated by the transformation of products into versatile heterocyclic motifs. Mechanistic studies revealed an in situ activation of the Co(II)/dppBz precatalyst by the carboxylate salt to generate a Co(I)‐species, which is presumed to be the active catalyst.
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- Award ID(s):
- 2155003
- PAR ID:
- 10468094
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Chemistry – A European Journal
- Volume:
- 29
- Issue:
- 58
- ISSN:
- 0947-6539
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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