Aryne‐Induced Novel Tandem 1, 2‐Addition/(3+2) Cycloaddition to Generate Imidazolidines and Pyrrolidines. Issue 34 (3rd July 2015)

• Record Type: Journal Article
• Authors: Swain, Sharada P.; Shih, Yi‐Chun; Tsay, Shwu‐Chen; Jacob, Joby; Lin, Chun‐Cheng; Hwang, Kuo Chu; Horng, Jia‐Cherng; Hwu, Jih Ru
• Is Part Of: Angewandte Chemie international edition. Volume 54:Issue 34(2015)
• Page Start: 9926
• Page End: 9930
• Publication Date: 2015-07-03
• Subjects: 1, 3‐dipolar cycloaddition -- arynes -- azomethine ylides -- imidazolidines -- pyrrolidines; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201503319
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: A new "single‐flask" method was developed for the synthesis of imidazolidines and pyrrolidines with high stereoselectivity. First, a Schiff base was arylated with an aryne. Second, an intramolecular proton transfer took place from the methylene position to the anionic aryne ring. Third, the resultant ylide reacted with a second equivalent of the same Schiff base in situ or an electron‐deficient alkene through a (3+2) cycloaddition. These sequential tandem 1, 2‐addition/(3+2) cycloaddition reactions led to the desired heterocycles in 63–88 % yields. Abstract : Two steps in one flask : A sequence of arylation of a Schiff base, an intramolecular proton transfer from the methylene position to the anionic aryne ring, and reaction of the resulting ylide with either a second equivalent of Schiff base or an electron‐deficient alkene in a (3+2) cycloaddition generates imidazolidines and pyrrolidines in high stereoselectivity and 63–88 % yields.