Synthesis of Optically Active Constrained 2-Substituted Norstatines: A Straightforward Application of Seebach's “SRS” Synthetic Principle
摘要:
A straightforward two-step methodology of synthesis of optically active (2,R)-substituted norstatines via addition of N-tert-butoxycarbonyl-substituted aldimines to (2S)-chiral enolates of 1,3-dioxolan-4-ones has been developed. In particular, the use of the natural (2S)-malic acid is examined for the synthesis of potential GABAergic spirocyclic gamma-lactams.
self-regeneration of stereocenters and has been applied to additionreactions among a selected number of imines and (2S)-chiral enolates of 1,3-dioxolan-4-ones. These reagents are easily available from the acetalization of (S)-alpha-hydroxy acids (lactic, mandelic, isovaleric, malic) and pivalaldehyde or pinacolone. In several cases, the addition of the enolate to the imine, the cyclization, and the removal of
A straightforward two-step methodology of synthesis of optically active (2,R)-substituted norstatines via addition of N-tert-butoxycarbonyl-substituted aldimines to (2S)-chiral enolates of 1,3-dioxolan-4-ones has been developed. In particular, the use of the natural (2S)-malic acid is examined for the synthesis of potential GABAergic spirocyclic gamma-lactams.
Synthesis of chiral β2,2,3-3-amino-2-hydroxyalkanoates and 3-alkyl-3-hydroxy-β-lactams by double asymmetric induction
作者:Andrea Guerrini、Greta Varchi、Rizzo Daniele、Cristian Samorì、Arturo Battaglia
DOI:10.1016/j.tet.2007.05.069
日期:2007.8
Reactions of chiral (2S)-enolates of dioxolan-4-ones, derived from lactic, mandelic, and phenyllactic acids, with aliphatic (SS)- and (SR)-tert-butylsulfinyl aldimines afforded conformationally restrained C2-disubstituted N,O-orthogonally protected 3-amino-2-hydroxyalkanoates in the form of N-sulfinyl protected 1′-aminodioxolan-4-ones. The product distribution showed that there is significant kinetic