Direct Mannich reaction of glycinate Schiff bases with N-(8-quinolyl)sulfonyl imines: a catalytic asymmetric approach to anti-alpha,beta-diamino esters.
An efficient catalytic enantioselective direct Mannich reaction of glycinate Schiff bases with aryl imines leading to anticonfigured orthogonally protected alpha,beta-diaminoesters has been realized. Keys to success in this new catalyst system are the use of Fesulphos/Cu(CH3CN)4PF6 (3-5 mol%) as a Lewis acid catalyst and readily available N-(8-quinolyl)sulfonyl-protected aldimines as substrates, affording excellent levels of diastereo- (typically anti/syn > 90:10) and enantiocontrol (typically > or = 90% ee). A remarkable feature of this catalyst system is that it allows the construction of products with a tetrasubstituted carbon stereocenter at C-alpha in a highly diastereo- and enantiocontrolled manner.
Hernández-Toribio
Jorge
J
Departamento de Química Orgánica, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain.
Gómez Arrayás
Ramón
R
Carretero
Juan C
JC
D000588:Amines / Q000737:chemistry*; D016227:Benzoquinones / Q000737:chemistry*; D002384:Catalysis; D004952:Esters / Q000737:chemistry*; D005998:Glycine / Q000737:chemistry; D007097:Imines / Q000737:chemistry*; D008352:Mannich Bases / Q000737:chemistry; D015394:Molecular Structure; D012545:Schiff Bases / Q000737:chemistry; D013237:Stereoisomerism; D013450:Sulfones / Q000737:chemistry*
D000588:Amines; D016227:Benzoquinones; D004952:Esters; D007097:Imines; D008352:Mannich Bases; C482356:N-sulfonylimine; D012545:Schiff Bases; D013450:Sulfones; C004532:quinone; D005998:Glycine