Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
Org Biomol Chem. 2012 Jan 21;10(3):516-23. doi: 10.1039/c1ob06528a. Epub 2011 Nov 16.
The intramolecular hydroamination of N-(ortho-alkynyl)aryl-N'-substituted trifluoroacetamidines and bromodifluoroacetamidines is studied in detail. When the substituents on the alkyne fragment are aryl and alkyl groups, 5-endo-dig cyclization occurs utilizing NaAuCl(4)·2H(2)O as a catalyst, while 6-exo-dig cyclization proceeds in the presence of K(2)CO(3) as a base. Interestingly, the indole derivatives are afforded with good regioselectivity via a 5-endo-dig pathway catalyzed by Cu(OAc)(2) when ortho-ethynyl appears on the aryl substituent of the amidine. The electrophilic cyclization of the amidines also shows good regioselectivity under the I(2)/NaHCO(3) system. At the end, a facile cascade synthesis of fluorinated quinazolones is described via hydroamination/ozonolysis from the corresponding amidine.
详细研究了 N-(邻炔基)芳基-N'-取代三氟乙酰胺和溴代二氟乙酰胺的分子内氢胺化反应。当炔烃片段上的取代基为芳基和烷基时，利用 NaAuCl(4)·2H(2)O 作为催化剂发生 5-endo-dig 环化，而在 K(2)CO(3)作为碱的存在下则发生 6-exo-dig 环化。有趣的是，当芳基取代的 amidine 中的邻炔基为乙基时，通过 Cu(OAc)(2)催化的 5-endo-dig 途径可以得到具有良好区域选择性的吲哚衍生物。在 I(2)/NaHCO(3)体系中，酰胺的亲电环化也具有良好的区域选择性。最后，通过相应的 amidine 的氢胺化/臭氧化反应，描述了一种通过氟喹唑啉的简便级联合成。
