A convenient method to construct (Z)-oxazines via 6-exo-dig iodocyclization and synthesis of indolin-3-one
作者:Jaya Kishore Vandavasi、Kung-Kai Kuo、Wan-Ping Hu、Ho-Chanu Shen、Wei-Sheng Lo、Jeh-Jeng Wang
DOI:10.1039/c3ob41272e
日期:——
An efficient regio-, stereo- and chemo-specific synthesis of 1,3-benzoxazines via 6-exo-dig cyclization to afford the Z-isomer is reported. The structure and connectivity were confirmed unambiguously on the basis of 1H NMR, NOESY, and ORTEP. Furthermore, DFT studies revealed that the Z-isomer was more stable than the E-isomer. Iodine substituted 1,3-benzoxazines were very useful precursors for cross coupling reactions. Suzuki reaction was carried out successfully and the resulting product was transformed to 1-(4-nitrobenzoyl)-2,2-diphenylindolin-3-one in the presence of a Lewis acid.
据报道,通过 6-exo-dig 环化可有效合成 1,3-苯并恶嗪,得到 Z-异构体。结构和连接性在 1H NMR、NOESY 和 ORTEP 的基础上得到明确证实。此外,DFT 研究表明 Z 异构体比 E 异构体更稳定。碘取代的1,3-苯并恶嗪是用于交叉偶联反应的非常有用的前体。 Suzuki反应成功进行,所得产物在路易斯酸存在下转化为1-(4-硝基苯甲酰基)-2,2-二苯基二氢吲哚-3-酮。