Brønsted acid-catalyzed imine amidation.
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).
Rowland
Gerald B
GB
Department of Chemistry and Biochemistry, University of Mississippi, Coulter Hall, University, Mississippi 38677, USA.
Zhang
Haile
H
Rowland
Emily B
EB
Chennamadhavuni
Spandan
S
Wang
Yong
Y
Antilla
Jon C
JC