Conjugate additions of E-alkenylphosphonates to lithiated Schollkopf's bislactim ether: Stereocontrolled access to anti 2-amino-3-substituted-4-phosphonobutanoic acids

Article abstract of DOI:10.1016/0040-4039(96)01230-0

Highly face-selective Michael adition of lithiated Schollkopf's bislactim ether (derived from cyclo-[L-val-gly], 7) to E-alkenylphosphonates 2a-d and 1,3-butadienylphosphonate 2e allows a direct and stereocontrolled access to the excitatory amino acid analogues 2,3-anti-2-amino-3-substituted-4-phosphonobutanoic acids 14a-d and 2-amino-6-phosphono-4-hexenoic acid 15. The relative stereochemistry was assigned from a NMR study of cyclic derivatives 16, 17 and 19.