Synthese homochiraler 3‐Oxa‐2,7‐diazabicyclo[3.3.0]octane aus Aminosäuren durch intramolekulare 1,3‐dipolare Cycloaddition von Nitronen

Abstract

Synthesis of Homochiral 3‐Oxa‐2,7‐diazabicyclo[3.3.0]octanes from Amino Acids by Intramolecular 1,3‐Dipolar Cycloaddition of Nitrones N 1‐Allylamino alcohols 9 were prepared from amino acids by various methods. Swern oxidation of 9 afforded aldehydes 11 . By reaction of 11 with N 1‐alkylhydroxylamines nitrone intermediates 4 were formed which spontaneously underwent an intramolecular 1,3‐dipolar cycloaddition to yield the bicyclic compounds 6 . The cycloaddition proceeds diastereoselectively furnishing homochiral compounds 6 from homochiral starting materials. The structure of 6aA was confirmed by X‐ray structural analysis.