Enzymatic Resolution of Aminocyclopentenols as Precursors to <scp>d</scp>- and <scp>l</scp>-Carbocyclic Nucleosides
作者:Mark J. Mulvihill、Jennifer L. Gage、Marvin J. Miller
DOI:10.1021/jo972265a
日期:1998.5.1
Racemic cis-4-aminocyclopent-2-en-1-ols were synthesized in three steps utilizing hetero Diels-Alder chemistry. Starting from suitably protected hydroxylamines, oxidization with sodium periodate and trapping with cyclopentadiene afforded cycloadducts (+/-)-5a-d. The N-O bond of the cycloadducts was reduced with Mo(CO)(6) to afford (+/-)-cis-4-aminocyclopent-2-en-1-ols (+/-)-6a-d. These compounds, or their corresponding acetates, were kinetically resolved by enzymatic acetylation or hydrolysis, respectively. Enzymatic acetylation of cis-N-(benzylcarbamoyl)-4-aminocyclopent-2-enol [(+/-)-6a] with Candida antarctica B lipase and Pseudomonas species lipase gave the corresponding acetate (-)-7a in 90% and 92% ee, respectively, after 40% conversion. Enzymatic hydrolysis of cis-N-acetyl-4-aminocyclopent-2-enol 1-O-acetate (+/-)-7d with electric eel acetylcholine esterase was successful in providing both cis-N-acetyl-4-aminocyclopent-2-enols (+)ed and (+)-7d in 92% ee (99% ee after a single recrystallization) after 40% conversion. Further synthetic transformations of these resolved synthetic building blocks and derivatives are also reported.