Direct alkenylation of 2-substituted azaarenes with carbonyls via CH bond activation using iron-based metal-organic framework Fe3O(BPDC)3 as an efficient heterogeneous catalyst

• Fe3O(BPDC)3 was used as catalyst for the synthesis of 2-alkenylazaarenes.
• High yields of 2-alkenylazaarenes were achieved.
• The catalyst could be recovered and reused.

A porous crystalline metal-organic framework Fe3O(BPDC)3 was synthesized from the reaction of biphenyl-4,4′-dicarboxylic acid and iron(III) chloride hexahydrate by a solvothermal method in the presence of acetic acid, and was characterized by using a variety of different techniques. The Fe3O(BPDC)3 could be used as an efficient heterogeneous catalyst in the synthesis of 2-alkenylazaarenes using the direct alkenylation of 2-substituted azaarenes with carbonyls via CH bond activation. The presence of acetic acid as a co-catalyst accelerated the transformation significantly. The Fe3O(BPDC)3 exhibited better performance in this transformation then other MOFs such as Fe3O(BDC)3, Cu2(OBA)2(BPY), Cu2(BDC)2(DABCO), Ni2(BDC)2(DABCO), Zn-MOF-74, and Cu2(NDC)2(DABCO). The Fe3O(BPDC)3 also exhibited higher catalytic activity than that of several homogeneous catalysts such as FeCl2, FeCl3, CuCl2, Zn(OAc)2, Zn(NO3)2, and Ni(OAc)2. The Fe3O(BPDC)3 catalyst could be recovered and reused several times in the synthesis of 2-alkenylazaarenes without a significant degradation in catalytic activity. To the best of our knowledge, 2-alkenylazaarenes was not previously synthesized via the direct alkenylation of 2-substituted azaarenes with carbonyls using heterogeneous catalysts.

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