Expedient Synthesis of C‐Aryl Carbohydrates by Consecutive Biocatalytic Benzoin and Aldol Reactions |
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Authors: | Karel Hernández Dr. Teodor Parella Dr. Jesús Joglar Dr. Jordi Bujons Prof. Dr. Martina Pohl Prof. Dr. Pere Clapés |
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Affiliation: | 1. Biotransformation and Bioactive Molecules Group, Instituto de Química Avanzada de Catalu?a, IQAC‐CSIC. Jordi Girona 18‐26, 08034 Barcelona (Spain), Fax: (+34)?932045904;2. Servei de Ressonància Magnètica Nuclear. Dept Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Cerdanyola del Vallès (Spain);3. IBG‐1: Biotechnologie, Forschungszentrum Jülich GmbH, 52425 Jülich (Germany) |
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Abstract: | The introduction of aromatic residues connected by a C?C bond into the non‐reducing end of carbohydrates is highly significant for the development of innovative structures with improved binding affinity and selectivity (e.g., C?aril‐sLex). In this work, an expedient asymmetric “de novo” synthetic route to new aryl carbohydrate derivatives based on two sequential stereoselectively biocatalytic carboligation reactions is presented. First, the benzoin reaction of aromatic aldehydes to dimethoxyacetaldehyde is conducted, catalyzed by benzaldehyde lyase from Pseudomonas fluorescens biovar I. Then, the α‐hydroxyketones formed are reduced by using NaBH4 yielding the anti diol. After acetal hydrolysis, the aldol addition of dihydroxyacetone, hydroxyacetone, or glycolaldehyde catalyzed by the stereocomplementary D ‐fructose‐6‐phosphate aldolase and L ‐rhamnulose‐1‐phosphate aldolase is performed. Both aldolases accept unphosphorylated donor substrates, avoiding the need of handling the phosphate group that the dihydroxyacetone phosphate‐dependent aldolases require. In this way, 6‐C‐aryl‐L ‐sorbose, 6‐C‐aryl–L ‐fructose, 6‐C‐aryl–L ‐tagatose, and 5‐C‐aryl‐L ‐xylose derivatives are prepared by using this methodology. |
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Keywords: | aldolases benzaldehyde lyase carbohydrates C C bond formation enzyme catalysis |
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