Hydrogen exchange, alkylation and acylation of potentially tautomeric methyl and methylidene derivatives of pyridine and diazines (Review)

“…This finding is consistent with the role of the Fe site as a base in the mechanism and the known pKas of the sp 3 and sp 2 sites. [28][29][30] The product of deprotonation, INT-2a is dearomatized and more stable than INT-2b, the corresponding intermediate from sp 2 C-H activation (G°298K = -4.2 vs. 16.1 kcal mol -1 ). Based on our current understanding, it is likely that the proposed mechanistic network is accessible for the entire series of substrates, but that differing substitution patterns on pyridine influence the barrier heights and relative thermodynamic stability of the products.…”

mentioning

confidence: 99%

Diverse Reactivity of an Iron–Aluminium Complex with Substituted Pyridines

Gorgas

White

Crimmin

2022

Preprint

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The reaction of an Fe–Al complex with an array of substituted pyridines is reported. Depending on the substitution pattern of the substrate site-selective sp2 or sp3 C–H bond activation is observed. A series of reaction products are observed based on (i) C–Al bond formation, (ii) C–C bond formation by nucleophilic addition or (iii) deprotonation of the β-diketiminate ligand. A divergent set of mechanisms involving a common intermediate is proposed.

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