Issue 23, 2023

Controlled reductive C–C coupling of isocyanides promoted by an aluminyl anion

Abstract

We report the reaction of the potassium aluminyl, K[Al(NON)] ([NON]2− = [O(SiMe2NDipp)2]2−, Dipp = 2,6-iPr2C6H3) with a series of isocyanide substrates (R-NC). In the case of tBu-NC, degradation of the isocyanide was observed generating an isomeric mixture of the corresponding aluminium cyanido-κC and -κN compounds, K[Al(NON)(H)(CN)]/K[Al(NON)(H)(NC)]. The reaction with 2,6-dimethylphenyl isocyanide (Dmp-NC), gave a C3-homologation product, which in addition to C–C bond formation showed dearomatisation of one of the aromatic substituents. In contrast, using adamantyl isocyanide Ad-NC allowed both the C2- and C3-homologation products to be isolated, allowing a degree of control to be exercised over the chain growth process. These data also show that the reaction proceeds through a stepwise addition, supported in this study by the synthesis of the mixed [(Ad-NC)2(Dmp-NC)]2− product. Computational analysis of the bonding within the homologised products confirm a high degree of multiple bond character in the exocyclic ketenimine units of the C2- and C3-products. In addition, the mechanism of chain growth was investigated, identifying different possible pathways leading to the observed products, and highlighting the importance of the potassium cation in formation of the initial C2-chain.

Graphical abstract: Controlled reductive C–C coupling of isocyanides promoted by an aluminyl anion

Supplementary files

Article information

Article type
Edge Article
Submitted
15 mar. 2023
Accepted
12 maí 2023
First published
12 maí 2023
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2023,14, 6278-6288

Controlled reductive C–C coupling of isocyanides promoted by an aluminyl anion

M. J. Evans, M. D. Anker, C. L. McMullin and M. P. Coles, Chem. Sci., 2023, 14, 6278 DOI: 10.1039/D3SC01387A

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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