Optically Active 3-Amino-3-Pyrrolidones by Reductive N-N-Bond Cleavage of 1-Pyrazolines Derived from (U)-3- Hydroxybutyric Acid
作者:Annett Bartels、Jürgen Liebscher
DOI:10.1080/00397919908085757
日期:1999.1
Abstract Raney-Ni-catalyzed hydrogenation of 1-pyrazoline-3-carboxylic acid derivatives 3 affords opticallyactive 4-substituted trans-3-amino-2-pyrrolidones 6 as new unnatural α, γ-diaminoacid derivatives by reductive N-N-bond cleavage, ring transformation and retro-aldol reaction.
Enantioselective synthesis of hydroxyalkylcyclopropanecarboxylic acid derivatives
作者:Anett Bartels、Jürgen Liebscher
DOI:10.1016/0957-4166(94)80109-6
日期:1994.8
Cycloaddition of diazomethane to enantiomerically pure 5-alkylidene-1,3-dioxane-4-ones 1 affords spiropyrazolines 2. Upon irradiation these products loose N-2 giving cyclopropanes 3 that are spiro annellated to the 5-position of the 1,3-dioxane-4-one ring. Both transformations are highly stereoselective giving rise to essentially pure enantiomers in quantitative yields.
Stereoselective Diazoalkane Cycloadditions to Chiral 5-Alkylidene-1,3-dioxan-4-ones and 3-Benzylidene-β-lactones