- Synthesis of conformationally restricted 1,2,3-triazole-substituted ethyl β- and γ-aminocyclopentanecarboxylate stereoisomers. Multifunctionalized alicyclic amino esters
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Stereoisomers of 1,2,3-triazole-functionalized, conformationally restricted β- or γ-amino esters with a cyclopentane skeleton were efficiently synthetized from the bicyclic β-lactam 6-azabicyclo[3.2.0]hept-3-en-7-one (1) and Vince γ-lactam (15) in five or six steps involving the azide-alkyne 1,3-dipolar cycloaddition of azido-substituted amino ester stereoisomers with nonsymmetric acetylenes. The azide-alkyne click reactions were investigated under thermal and Cu(I)-catalyzed conditions. Surprisingly, the thermally induced cycloaddition furnished the corresponding 1,4-triazoles regioselectively, which also took place selectively in response to Cu(I) catalysis.
- Kiss, Loránd,Forró, Eniko,Sillanp??, Reijo,Fül?p, Ferenc
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- Synthesis of highly functionalized cyclopentanes as precursors of hydroxylated azidocarbonucleosides
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Regio- and stereoisomers of functionalized azido amino alcohols with a cyclopentane skeleton were synthesized in enantiomerically pure forms. Enzymatic ring cleavage of racemic2-azabicyclo[2.2.1]hept-5-en-3-one gave the corresponding amino acid and one enantiomer of the lactam stereospecifically. These were protected by esterification and carbamoylation, and then epoxidized. The resulting oxiranes underwent cleavage by sodium azide with complementary stereoselectivities. The regioisomeric products were easily separated by crystallization or column chromatography.
- Kiss, Lorand,Forro, Enikoe,Sillanpaeae, Reijo,Fueloep, Ferenc
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experimental part
p. 153 - 160
(2010/04/02)
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