Synthesis of (Z)-β-(Carbonylamino)alkenylindium through Regioselective anti-Carboindation of Ynamides and Its Transformation to Multisubstituted Enamides |
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Authors: | Kyoungmin Kang Kosuke Sakamoto Dr. Yoshihiro Nishimoto Prof. Dr. Makoto Yasuda |
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Affiliation: | 1. Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, Japan;2. Frontier Research Base for Global Young Researchers Center, for Open Innovation Research and Education (COiRE), Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, Japan |
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Abstract: | The regioselective anti-carboindation of ynamides by using InBr3 and silylated nucleophiles was developed to synthesize (Z)-β-(carbonylamino)alkenylindiums. The X-ray crystallographic analysis of an alkenylindium suggested that the reaction proceeded in an anti-addition fashion. In contrast to reported syn-carbometalations of ynamides by using organometallics, a cooperation of InBr3 and silylated nucleophiles to ynamides achieved an anti-addition, which was supported by DFT calculations. The scope of substrates included various ynamides and silylated nucleophiles, such as silyl ketene acetals and silyl ketene imines. The transformation of synthesized alkenylindiums by iodination, radical coupling, and Pd-catalyzed cross-coupling successfully afforded trisubstituted enamines with high regio- and stereoselectivities. |
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Keywords: | carbometalation indium Lewis acids silicon ynamides |
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