Addition of dilithiated methyl-3-aminobutanoate to aldehydes proceeds with ul-1,2-induction

Article abstract of DOI:10.1016/S0040-4039(00)76697-4

Syntheses of 2-substituted 1-hydroxyethylene building blocks, useful as the central moiety of HIV-1 protease inhibitors, is described. Dilithiated N-protected-3-amino-4-phenylbutanoic methyl esters are reacted with aldehydes to give predominantly aldol products with l,u configuration. The diastereomeric ratio depends on the N-protecting group and on the experimental conditions. The configurations are assigned by ¹H-NMR of cyclic derivatives and are supported by X-ray structure.