Aryne-Induced Novel Tandem 1,2-Addition/(3+2) Cycloaddition to Generate Imidazolidines and Pyrrolidines

Sharada P Swain; Yi-Chun Shih; Shwu-Chen Tsay; Joby Jacob; Chun-Cheng Lin; Kuo Chu Hwang; Jia-Cherng Horng; Jih Ru Hwu

doi:10.1002/anie.201503319

Aryne-Induced Novel Tandem 1,2-Addition/(3+2) Cycloaddition to Generate Imidazolidines and Pyrrolidines

Angew Chem Int Ed Engl. 2015 Aug 17;54(34):9926-30. doi: 10.1002/anie.201503319. Epub 2015 Jul 3.

Authors

Sharada P Swain¹, Yi-Chun Shih¹, Shwu-Chen Tsay^{1

2}, Joby Jacob¹, Chun-Cheng Lin¹, Kuo Chu Hwang¹, Jia-Cherng Horng¹, Jih Ru Hwu^{3

4}

Affiliations

¹ Department of Chemistry and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013 (Taiwan).
² Department of Chemistry, National Central University, Jhongli City 32001 (Taiwan).
³ Department of Chemistry and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013 (Taiwan). jrhwu@mx.nthu.edu.tw.
⁴ Department of Chemistry, National Central University, Jhongli City 32001 (Taiwan). jrhwu@mx.nthu.edu.tw.

PMID: 26138269
DOI: 10.1002/anie.201503319

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.

Keywords: 1,3-dipolar cycloaddition; arynes; azomethine ylides; imidazolidines; pyrrolidines.