Synthesis of Cyclic N-Acyl Amidines by [3 + 2] Cycloaddition of N-Silyl Enamines and Activated Acyl Azides |
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Authors: | Dong Geun Jo Changeun Kim Sinjae Lee Sooyeon Yun Seewon Joung |
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Institution: | Department of Chemistry, Mokpo National University, Muan 58554, Korea; (D.G.J.); (C.K.); (S.L.); (S.Y.) |
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Abstract: | In this study, we describe the synthesis of cyclic N-acyl amidines from readily available N-heteroarenes. The synthetic methodology utilized the versatile N-silyl enamine intermediates from the hydrosilylation of N-heteroarenes for the 3 + 2] cycloaddition reaction step. We evaluated various acyl azides and selected an electronically activated acyl azide, thereby achieving a reasonable yield of cyclic N-acyl amidines. We analyzed the relationship between the reactivity of each step and the electronic nature of substrates using in situ nuclear magnetic resonance spectroscopy. In addition, we demonstrated gram-scale synthesis using the proposed methodology. |
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Keywords: | [3 + 2] cycloaddition N-silyl enamine B(C6F5)3 tetrahydroisoquinoline acyl azide spectroscopic analysis |
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