The resolution of chiral nitrones via derivatization of hydroxylamines was applied to MiPNO, a new, stable, easily prepared chiral cyclic nitrone. The application of MiPNO in totally regio- and diastereo-selective 1,3-dipolar cycloaddition reactions provides an expeditious enantioselective access to unusual gamma-hydroxy alpha-amino acids.
MiPNO, a New Chiral Cyclic Nitrone for Enantioselective Amino Acid Synthesis:The Cycloaddition Approach. -Nitrone (IV) is resolved via O-acylation of its hydroxylamine (V) with a chiral amino acid. Both the enantiomerically pure nitrone (IV) and the racemate undergo totally regio-and diastereoselective 1,3-dipolar cycloaddition reactions with a range of alkenes and one alkyne. The nitrone reacts from the less hindered side in an exo mode. The reductive cleavage of the N-O bond of the cycloadducts affords the corresponding amino alcohols. A one-pot conversion of cycloadduct (IXd) into enantiopure N-protected α-amino γ-lactone (XII) is also performed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.