Diastereodivergent Synthesis of 4-Hydroxy-2,3-methanopipecolic Acid Derivatives as Conformationally Constrained Homoserine Analogues
作者:Ernesto G. Occhiato、Andrea Casini、Antonio Guarna、Dina Scarpi
DOI:10.1002/ejoc.201100962
日期:2011.11
methylide were 1:4 to 1:7 in DMSO and diastereopure trans isomers were obtained by chromatography after OH-deprotection in 57–73 % yield. These compounds are new, conformationallyconstrained homoserine analogues potentially useful as conformational probes and for drug discovery in medicinal chemistry.
The synthesis of (2S,4R)- and (2R,4R)-4-hydroxypipecolic acid has been realized from commercial ethyl (R)-4-cyano-3-hydroxybutanoate through palladium-catalyzed methoxycarbonylation of a 4-hydroxy-substituted lactam-derived vinyl phosphate followed by the stereocontrolled reduction of the enamine double bond. The stereoselectivehydrogenation of the suitably 4-hydroxy-protected enantiomer afforded
Stereoselective Synthesis of (2S,4R)-4-Hydroxypipecolic Acid
作者:Ernesto G. Occhiato、Dina Scarpi、Antonio Guarna
DOI:10.1002/ejoc.200700849
日期:2008.1
A new synthetic route to enantiopure (2S,4R)-4-hydroxypipecolicacid from commercial ethyl (3S)-4-chloro-3-hydroxybutanoate is reported. The synthesis is based on the Pd-catalyzed methoxycarbonylation of a 4-alkoxy-substituted δ-valerolactam-derived vinyl triflate followed by the stereocontrolled hydrogenation of the enamine double bond. The final product was obtained after exhaustive hydrolysis in