Brønsted Acid-Catalyzed Imine Amidation

• Published in: Journal of the American Chemical Society Vol. 127; no. 45; pp. 15696 - 15697
• Main Authors: Rowland, Gerald B, Zhang, Haile, Rowland, Emily B, Chennamadhavuni, Spandan, Wang, Yong, Antilla, Jon C
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 16.11.2005; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Multidisciplinary; Exact sciences and technology; Organic chemistry; Physical Sciences; Science & Technology; ENAMINE; Catalytic reaction; Brönsted acid; Nucleophilic reaction; Enantioselectivity; Catalyst selectivity; Asymmetric reaction; Acid catalysis; Imine; Experimental study; Catalyst activity; Amidation
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja0533085

A new method for the Brønsted acid-catalyzed addition of amide nucleophiles to imines to produce protected aminal products is described. Simple Brønsted acids (phenyl phosphinic acid and trifluoromethanesulfonimide) were shown to be excellent catalysts, providing high yields of the aminal product. A catalytic asymmetric imine amidation using sulfonamides as nucleophiles was successful when a hindered biaryl phosphoric acid catalyst derived from 2,2‘-diphenyl-[3,3‘-biphenanthrene]-4,4‘-diol (VAPOL) was used. Excellent yields and enantioselectivities were found in these additions (up to 99% ee).