Total synthesis of (−)-codonopsinine via regioselective and diastereoselective amination using chlorosulfonyl isocyanate. Issue 30 (27th July 2017)

• Record Type: Journal Article
• Authors: Choi, Young Jae; Kim, Yoo Chang; Park, Sook Jin; Jung, Jun Min; Kim, Yeon Su; Kim, In Su; Jung, Young Hoon
• Is Part Of: Tetrahedron. Volume 73:Issue 30(2017)
• Page Start: 4458
• Page End: 4463
• Publication Date: 2017-07-27
• Subjects: Amidomercuration -- Amination -- Chlorosulfonyl isocyanate -- Codonopsinine -- Natural product; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2017.06.002
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: The total synthesis of (−)-codonopsinine (1 ) from the readily available ( S )-3-chloropropan-1, 2-diol is described. The key steps for the preparation of (−)-codonopsinine (1 ) involve the regioselective and diastereoselective amination of anti -1, 2-dibenzyl ether11 using chlorosulfonyl isocyanate and intramolecular amidomercuration to form the pyrrolidine ring. Notably, the reaction between anti -1, 2-dibenzyl ether and chlorosulfonyl isocyanate in toluene at 0 °C produced the corresponding anti -1, 2-amino alcohol12a as a major product with excellent diastereoselectivity ( anti : syn = 29:1). This observation can be explained by the neighboring group participation leading to the retention of stereochemistry. Graphical abstract: