Chiral N-phosphonyl imine chemistry: asymmetric synthesis of alpha,beta-diamino esters by reacting phosphonyl imines with glycine enolates.
Chiral phosphonyl imines attached with N-isopropyl protection group were found to react with lithium glycine enolates under convenient conditions to give alpha,beta-diamino esters. Thirteen examples have been examined in good to excellent chemical yields (85-97%) diastereoselectivity (up to 99% de). By treating with HBr at room temperature, the chiral auxiliary can be readily removed and recycled. The absolute structure has been unambiguously determined by converting a product to a known sample.
Ai
Teng
T
Department of Chemistry and Biochemistry, Texas Tech University Lubbock, TX 79409-1061, USA.
Li
Guigen
G
D004952:Esters; D005998:Glycine / Q000737:chemistry*; D007097:Imines / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry; D013237:Stereoisomerism
D004952:Esters; D007097:Imines; D008094:Lithium; D005998:Glycine