Gross Johannes, Prokop Zbyněk, Janssen Dick, Faber Kurt, Hall Mélanie
Department of Chemistry, University of Graz, Heinrichstrasse 28, 8010, Graz, Austria.
Department Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5A13, 625 00, Brno, Czech Republic.
Chembiochem. 2016 Aug 3;17(15):1437-41. doi: 10.1002/cbic.201600227. Epub 2016 Jun 22.
The hydrolytic dehalogenation of rac-1,3-dibromobutane catalyzed by the haloalkane dehalogenase LinB from Sphingobium japonicum UT26 proceeds in a sequential fashion: initial formation of intermediate haloalcohols followed by a second hydrolytic step to produce the final diol. Detailed investigation of the course of the reaction revealed favored nucleophilic displacement of the sec-halogen in the first hydrolytic event with pronounced R enantioselectivity. The second hydrolysis step proceeded with a regioselectivity switch at the primary position, with preference for the S enantiomer. Because of complex competition between all eight possible reactions, intermediate haloalcohols formed with moderate to good ee ((S)-4-bromobutan-2-ol: up to 87 %). Similarly, (S)-butane-1,3-diol was formed at a maximum ee of 35 % before full hydrolysis furnished the racemic diol product.
来自日本鞘氨醇单胞菌UT26的卤代烷脱卤酶LinB催化外消旋1,3 - 二溴丁烷的水解脱卤反应按顺序进行：首先形成中间体卤代醇，然后进行第二步水解反应生成最终的二醇。对反应过程的详细研究表明，在第一个水解步骤中，仲卤原子发生亲核取代反应，具有明显的R对映选择性。第二步水解反应在伯位发生区域选择性转变，优先选择S对映体。由于所有八种可能反应之间存在复杂的竞争，形成的中间体卤代醇具有中等至良好的对映体过量值（(S)-4 - 溴丁 - 2 - 醇：高达87%）。同样，在完全水解生成外消旋二醇产物之前，(S)-1,3 - 丁二醇的对映体过量值最高为35%。
