Asymmetric syntheses of all four isomers of 4-amino-4-carboxyproline: Novel conformationally restricted glutamic acid analogues

Article abstract of DOI:10.1016/0957-4166(95)00209-8

Asymmetric syntheses of all four isomers of 4-amino-4-carboxyprolines, i.e. (2S,4S)-3, (2S,4R)-4, and their corresponding enantiomers, as novel conformationally restricted analogues of glutamic acid, were performed from trans-4-hydroxy-L-proline as a homochiral starting material. The key step was the spirohydantoin ring formation by employing the Bucherer-Bergs reaction of 4-oxoproline derivatives. These structures were determined by NMR studies.