Hao Ya-Cheng, Zong Min-Hua, Wang Zhi-Lin, Li Ning
School of Food Science and Engineering, South China University of Technology, 381 Wushan Road, Guangzhou, 510640, China.
Agro-Biological Gene Research Center, Guangdong Academy of Agricultural Sciences, 20 Jinying Road, Guangzhou, 510640, China.
Bioresour Bioprocess. 2021 Aug 27;8(1):80. doi: 10.1186/s40643-021-00435-w.
Chiral furfuryl alcohols are important precursors for the synthesis of valuable functionalized pyranones such as the rare sugar L-rednose. However, the synthesis of enantiopure chiral biobased furfuryl alcohols remains scarce. In this work, we present a chemoenzymatic route toward enantiopure nitrogen-containing (R)- and (S)-3-acetamido-5-(1-hydroxylethyl)furan (3A5HEF) from chitin-derived N-acetyl-D-glucosamine (NAG).
3-Acetamido-5-acetylfuran (3A5AF) was obtained from NAG via ionic liquid/boric acid-catalyzed dehydration, in an isolated yield of approximately 31%. Carbonyl reductases from Streptomyces coelicolor (ScCR) and Bacillus sp. ECU0013 (YueD) were found to be good catalysts for asymmetric reduction of 3A5AF. Enantiocomplementary synthesis of (R)- and (S)-3A5HEF was implemented with the yields of up to > 99% and the enantiomeric excess (ee) values of > 99%. Besides, biocatalytic synthesis of (R)-3A5HEF was demonstrated on a preparative scale, with an isolated yield of 65%.
A two-step process toward the chiral furfuryl alcohol was successfully developed by integrating chemical catalysis with enzyme catalysis, with excellent enantioselectivities. This work demonstrates the power of the combination of chemo- and biocatalysis for selective valorization of biobased furans.
手性糠醇是合成有价值的功能化吡喃酮（如稀有糖L-赤藓糖）的重要前体。然而，对映体纯的手性生物基糠醇的合成仍然很少。在这项工作中，我们提出了一条从几丁质衍生的N-乙酰-D-葡萄糖胺（NAG）制备对映体纯的含氮（R）-和（S）-3-乙酰氨基-5-（1-羟乙基）呋喃（3A5HEF）的化学酶促路线。
通过离子液体/硼酸催化脱水从NAG获得了3-乙酰氨基-5-乙酰基呋喃（3A5AF），分离产率约为31%。发现来自天蓝色链霉菌（ScCR）和芽孢杆菌属ECU0013（YueD）的羰基还原酶是3A5AF不对称还原的良好催化剂。实现了（R）-和（S）-3A5HEF的对映体互补合成，产率高达>99%且对映体过量（ee）值>99%。此外，在制备规模上证明了（R）-3A5HEF的生物催化合成，分离产率为65%。
通过将化学催化与酶催化相结合，成功开发了一种制备手性糠醇的两步法，具有优异的对映选择性。这项工作证明了化学催化和生物催化相结合对生物基呋喃进行选择性增值的能力。
