Absolute Configuration of optically active aminophosphonic acids

Synthesis, molecular structure, and absolute configuration of an optically active (1-amino-2-phenylethyl) phosphonic acid monohydrate

“…So far, only a few optically active (1-aminoalky1)phosphonic acids have been obtained and the configurations have been unequivocally established only for the phosphonate analogues of valine ,5 alanine,6 and phenylglycine. 5 In this study we have synthesized both enantiomers of (2) from diethyl (l-oxo-2-phenylethyl)phosphonate, using the reported procedure7 to obtain racemic (l-amino-2-phenylethy1)phosphonate (1).…”

Double Asymmetric Induction in the Synthesis of Enantiomeric α‐Aminophosphonic Acids Mediated by Sulfinimines

“…The latter information strongly suggested that the stereochemical outcome of the addition of (–)‐ and (+)‐enantiomers of phosphite 1 to the (+)‐( S )‐ 2 is the same and should lead to the formation of the adducts 3 with ( S S R C ) configuration (entries 1 and 3), and addition of (+)‐ and (–)‐phosphites 1 to the (–)‐( R )‐ sulfinimine 2 should give the ( R S S C ) adducts as the major products (entries 2 and 4). Finally, the stereochemistry of the addition reaction of dimenthyl phosphites 1 to enantiomeric sulfinimines 2 was confirmed by purification of the adducts 3 (entries 1 and 4) and separation of the major diastereomers of 3 (entries 2 and 3) using flash chromatography and their acidic hydrolysis to the free α‐APs 4 for which the absolute configurations are known (Scheme ).…”

Addition of dimethyl phosphite to imines bearing the L‐methionine moiety and its surprisingly poor chiral assistance

“…The addition of dialkyl and diaryl phosphites to an azomethine bond of chiral Schiff bases, such as N ‐α‐methylbenzylimines, has been described in several papers 1–5. Diastereoselectivity of reported reactions varied from 2:1 to 9:1 of a diastereoisomeric ratio.…”