Enzymatic Transformations 62. Preparative Scale Synthesis of Enantiopure Glycidyl Acetals using anAspergillus niger Epoxide Hydrolase-Catalysed Kinetic Resolution

Autor: Bastien Doumèche, Roland Furstoss, Alain Archelas
Rok vydání: 2006
Předmět:
Zdroj: Advanced Synthesis & Catalysis. 348:1948-1957
ISSN: 1615-4169
1615-4150
Popis: The hydrolytic kinetic resolution of five glycidaldehyde acetal derivatives was examined using the recombinant Aspergillus niger epoxide hy- drolase as biocatalyst. This could successfully be per- formed, at room temperature, using solely deminer- alised water as solvent and following a two-phase methodology allowing us to operate at a global sub- strate concentration as high as 200 g/L in the reactor. The observed E values were shown to be modest to excellent, depending on the structure of the acetal moiety, indicating that it is possible to achieve this resolution very efficiently just by choosing the right substituents. Both the unreacted (R)-epoxide and the formed (S)-diol could thus be obtained in good to excellent ee (ee > 99 % for the epoxide). For the best substrates, the reaction could be performed within a few hours by using a biocatalyst over substrate mo- lecular ratio of about 9 to 10 × 10 4 mol %. The turn- over frequency (TOF) as well as the total turnover number (TON) of the enzyme proved to be excellent as compared to chemical catalysts - reaching respec- tively values in the order of 6 × 10 2 mol sub/mol enz/ min and 6 × 10 4 mol sub/mol enz. The space-time yield of the best (two-phase) reactor could thus reach a value as high as 56 g/L/hour. As a demon- stration experiment, a 50-g scale resolution of glyci- daldehyde 2,2-dimethyltrimethylene acetal was per- formed.
Databáze: OpenAIRE
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