Recyclable [Ru2Cl3(p-cymene)2][PF6]/Cu(OAc)2/PEG-400/H2O system for oxidative annulation of alkynes by aniline derivatives: Green synthesis of indoles. Issue 9 (2nd March 2017)

• Record Type: Journal Article
• Authors: Liao, Yang; Wei, Ting; Yan, Tao; Cai, Mingzhong
• Is Part Of: Tetrahedron. Volume 73:Issue 9(2017)
• Page Start: 1238
• Page End: 1246
• Publication Date: 2017-03-02
• Subjects: Ruthenium -- Recycling -- Oxidative annulation -- Indole -- Green chemistry; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2017.01.023
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: [Ru2 Cl3 ( p -cymene)2 ][PF6 ] in a mixture of PEG-400 and water is shown to be a highly efficient catalyst for the oxidative annulation of alkynes by N -2-pyrimidyl-substituted anilines bearing a removable directing group. The reaction could be conducted at 100 °C using Cu(OAc)2 ·H2 O (2.0 equiv) as oxidant, yielding a variety of indole derivatives in good to excellent yields. The isolation of the products was readily performed by extraction with petroleum ether and more importantly, both [Ru2 Cl3 ( p -cymene)2 ][PF6 ] and Cu(OAc)2 in PEG-400/H2 O system could be easily recycled and reused six times without any loss of catalytic activity. Graphical abstract: