Diastereoselective Synthesis of 2‐Amino‐4‐phosphonobutanoic Acids by Conjugate Addition of Lithiated Schoellkopf′s Bislactim Ethers to Vinylphosphonates.

Abstract

Organo-phosphorus compounds Organo-phosphorus compounds S 0080Diastereoselective Synthesis of 2-Amino-4-phosphonobutanoic Acids by Conjugate Addition of Lithiated Schoellkopf's Bislactim Ethers to Vinylphosphonates.-The conjugate addition to vinylphosphonates takes place regio-and stereoselectively. 2,5-trans Isomers are formed with high predominance (one exception). The reaction with β-substituted vinylphosphonates proceeds with high 2,1' diastereoselectivity yielding 2,1'-anti or 2,1'-syn products depending on the configuration of the vinylphosphonates. Starting from α-substituted and α,β-disubstituted vinylphosphonates, different results are obtained. The nature of the α-substituent has a strong effect on the reaction outcome. In these cases, the selectivity can be improved by treatment of intermediates with bulky proton sources like 2,4,6-tri-tert-butylphenol. The resulting products can easily be transformed into 2-amino-4-phosphonobutanoic acids which are of interest for biological studies. -(RUIZ*, M.; FERNANDEZ, M. C.; DIAZ, A.; QUINTELA, J. M.; OJEA*, V.; J. Org. Chem. 68 (2003) 20, 7634-7645; Dep. Quim. Fundam. Ind., Fac. Cienc., Univ. La Coruna, E-15071 La Coruna, Spain; Eng.) -Jannicke 06-138 2004 Organo-phosphorus compounds