碘化钾催化无保护8-氨基喹啉的选择性C(5)-芳基硫醚化和C(5),C(7)-双芳基硫醚化及吲哚C(2),C(3)-双芳基硫醚化反应

KI-Catalyzed Selective C(5)-Sulfenylation and C(5),C(7)-Disulfenylation of Unprotected 8-Aminoquinolines and the Indole C(2),C(3)-Disulfenylation

报道了采用2.5mol%碘化钾为唯一催化剂,无需任何过渡金属催条件下无保护8-氨基喹啉的碳-氢甲芳基硫醚化反应.有趣的是,通过简单调控反应时间和介质可以实现选择性的C(5)-芳基硫醚化和C(5),C(7)-双芳基硫醚化.在对二甲苯中反应12h时为C(5)-芳基硫醚化.另一方面,延长反应时间至24h并更换反应介质为甲苯则选择性地发生C(5),C(7)-双芳基硫醚化.此外,双芳基硫醚化反应可以扩展到吲哚类底物,实现含2,3-二芳基硫醚结构的吲哚合成.

The aromatic C—H sulfenylation reactions of unprotected 8-aminoquinolines have been realized by employing KI as the only catalyst at 2.5 mol%loading without using any transition metal reagent.Interestingly,the selective C(5)-sulfenylation and C(5),C(7)-disulfenylation have been successfully achieved by simply controlling the reaction time.Reaction time of 12 h in p-xylene enables the C(5)-sulfenylation.On the other hand,prolonging the reaction time to 24 h and switching the reaction medium to toluene lead to the selective C(5),C(7)-double sulfenylation.Moreover,the double sulfenylation has been extended to the indole substrate for the selective synthesis of 2,3-disulfenyl indoles.