Simple Brønsted acid catalyzed C–H functionalization: efficient access to poly-substituted pyridines. Issue 27 (6th July 2016)

• Record Type: Journal Article
• Authors: Lai, Shujun; Ren, Xuwen; Zhao, Jinzhong; Tang, Zhuo; Li, Guangxun
• Is Part Of: Tetrahedron letters. Volume 57:Issue 27/28(2016)
• Page Start: 2957
• Page End: 2961
• Publication Date: 2016-07-06
• Subjects: Hantzsch 1, 4-dihydropyridine -- C–H functionalization -- Imine -- Poly-substituted pyridine; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2016.05.061
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: An exceptionally simple and environmentally friendly methodology has been developed for the synthesis of poly-substituted pyridines with easily accessible substrates. Highlights: Benzylic C–H bond of pyridines were functionalized with ordinary aromatic imines. Simple Brønsted acids efficiently catalyzed the reactions. Poly-substituted pyridines were obtained from accessible aromatic Hantzsch esters. Abstract: An exceptionally simple and environmentally friendly methodology has been developed for directly functionalizing the benzylic C–H bond of the poly-substituted pyridines with aromatic imines. Simple Brønsted acid catalysts including salicylic acid and TsOH were successfully employed. Different types of poly-substituted pyridines could be efficiently obtained with moderate yields. Traditional ways to such types of pyridines involved the aromatization of the corresponding Hantzsch 1, 4-dihydropyridines, while this method greatly simplified the synthetic procedures.