Solvent/Oxidant-Switchable Synthesis of Multisubstituted Quinazolines and Benzimidazoles via Metal-Free Selective Oxidative Annulation of Arylamidines
Jian-Ping Lin, Feng-Hua Zhang and Ya-Qiu Long*
*CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China, Email: yqlongsimm.ac.cn
J.-P. Lin, F.-H. Zhang, Y.-Q. Long, Org. Lett., 2014, 16, 2822-2825.
DOI: 10.1021/ol500864r (free Supporting Information)
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A fast and simple reaction of amidines gave benzimidazoles via iodine(III)-promoted oxidative C(sp3)-C(sp2) bond formation in nonpolar solvents, whereas the use of polar solvents favoured a C(sp2)-N bond formation to yield quinazolines. Further selective synthesis of quinazolines in polar solvent was realized using TEMPO as catalyst and K2S2O8 as the oxidant. No metal, base, or other additives were needed.
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