Heteroarylidene-tethered bis(oxazoline) copper complexes catalyzed cascade reaction involving asymmetric Friedel–Crafts alkylation/N-hemiacetalization of indoles with β, γ-unsaturated α-ketoester. Issue 22 (3rd June 2015)

• Record Type: Journal Article
• Authors: Ma, Hong-Li; Li, Jia-Qi; Sun, Lu; Hou, Xu-He; Zhang, Zhen-Hua; Fu, Bin
• Is Part Of: Tetrahedron. Volume 71:Issue 22(2015)
• Page Start: 3625
• Page End: 3631
• Publication Date: 2015-06-03
• Subjects: Bis(oxazoline) -- Asymmetric catalysis -- Cascade -- Friedel–Crafts -- Indole; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2014.12.020
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: A convenient approach to the synthetically and biologically useful indole derivatives was developed. A cascade sequence involving Friedel–Crafts alkylation of 3-methyl indoles with β, γ-unsaturated α-ketoester followed by N-hemiacetalization were realized using heteroarylidene-tethered bis(oxazoline)-copper complexes. The pyrroloindole products with two chiral centers were obtained in high yields (85–95%) with both high diastereoselectivities (87:13–96:4 drs) and enantioselectivities (87–98% ees). A plausible mechanism was proposed. Graphical abstract: