Activation of sp3 and sp2 CH bonds of oxygen containing heterocyclic molecules for alkylation and arylation reactions catalyzed by an iron complex

• An efficient iron(III) complex of a bis(amido)pyridine ligand for activation of sp3 and sp2 CH bonds.
• CC coupling of oxygen containing heterocyclics with various alkyl, allyl and aryl Grignard reagents.
• Activation of selective α CH bond at room temperature and within a short period of time.
• Low catalyst loading (0.02–0.2 mol%) and high turnover frequency (>1700 h−1).

Activation of both sp3 and sp2 CH bonds is reported using an efficient iron(III) complex (1) of a ligand (N2,N6-bis(2,6-diisopropylphenyl)pyridine-2,6-dicarboxamide: L). The iron(III) complex showed catalytic activity of CC coupling reaction of oxygen containing heterocycles, e.g. tetrahydrofuran (THF), with various alkyl, allyl and aryl Grignard reagents under ambient reaction conditions. Complex 1 demonstrated excellent activity and reactions were completed within 30 min to 1 h. A high turnover frequency (TOF) of 1700 h−1 using a low catalyst loading of 0.02 mol% was obtained for the reaction. Interestingly, the catalyst was selective in activation of the CH bond adjacent to the oxygen in various oxygen containing heterocyclic molecules to yield 2-substitituted products.

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