Asymmetric intramolecular Friedel–Crafts reaction catalyzed by a spiropyrrolidine organocatalyst: Enantioselective construction of indolizine and azepine frameworks. Issue 45 (7th November 2018)

• Record Type: Journal Article
• Authors: Zhang, Yi-Hang; Yuan, Yong-Hai; Zhang, Shu-Yu; Tu, Yong-Qiang; Tian, Jin-Miao
• Is Part Of: Tetrahedron letters. Volume 59:Issue 45(2018)
• Page Start: 4015
• Page End: 4018
• Publication Date: 2018-11-07
• Subjects: Friedel–Crafts -- Spiro-pyrrolidine organocatalyst -- Enantioselective -- Indolizine and azepine; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2018.09.061
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: Highlight: Asymmetric Friedel-Crafts reaction using our SPD-type organocatalyst. Construction of azepine and indolizine frameworks in excellent ee. All-carbon quaternary center in indolizine frameworks was generated. Abstract: The asymmetric intramolecular Friedel–Crafts type Michael reaction of α, β-unsaturated aldehyde with pyrrole, catalyzed by a spiropyrrolidine (SP)-type organocatalyst, has been accomplished, which allows the construction of a series of azepine and indolizine frameworks with high to excellent enantioselectivities (up to 98% ee). Moreover, the substrate scope could be extended to generate a quaternary center in indolizine frameworks (up to 96% ee).