School of Chemistry, University of Hyderabad , Hyderabad 500 046, Andhra Pradesh, India.
J Org Chem. 2014 May 2;79(9):3963-72. doi: 10.1021/jo500424p. Epub 2014 Apr 23.
Ruthenium-catalyzed oxidative annulation of N-quinolin-8-yl-benzamides with alkynes in open air has been achieved using 8-aminoquinolinyl moiety as a bidentate directing group in the presence of Cu(OAc)2·H2O as an oxidant. This reaction offers a broad substrate scope, and both symmetrical and unsymmetrical alkynes can be applied. High regioselectivity was achieved in the case of unsymmetrical (aryl)alkynes. Reaction with heteroaryl amides was also successful in this catalytic process. A ruthenium-N-quinolin-8-yl-benzamide complex was isolated in the absence of alkyne; in the absence of both N-quinolin-8-yl-benzamide and alkyne, in contrast to literature, only the monoacetate complex RuCl(OAc)(p-cymene), but not the bis-acetate complex Ru(OAc)2(p-cymene), was isolated. These data suggest that this reaction may proceed via N,N-bidentate chelate complex. Key products were characterized by X-ray crystallography.
钌催化的 N-喹啉-8-基苯甲酰胺与炔烃在空气中的氧化环化反应，在 Cu(OAc)2·H2O 作为氧化剂的存在下，使用 8-氨基喹啉基部分作为双齿导向基团，实现了这一反应。该反应具有广泛的底物范围，可应用对称和非对称炔烃。在非对称（芳基）炔烃的情况下，实现了高区域选择性。在该催化过程中，杂芳基酰胺也能成功反应。在没有炔烃的情况下分离得到了钌-N-喹啉-8-基苯甲酰胺配合物；与文献相反，在没有 N-喹啉-8-基苯甲酰胺和炔烃的情况下，仅分离得到了单乙酸酯配合物 RuCl(OAc)(p-cymene)，而不是双乙酸酯配合物 Ru(OAc)2(p-cymene)。这些数据表明，该反应可能通过 N，N-双齿螯合配合物进行。关键产物通过 X 射线晶体学进行了表征。
