中国科学院化学研究所Haifeng Du团队在有机合成研究中取得进展。他们用手性硼磷酸盐实现了2-乙烯基苄醇的不对称分子内氢烷氧基化反应。相关论文发表在2022年3月11日出版的《德国应用化学》杂志上。

研究人员发现，B(C₆F₅)₃可催化2-乙烯基苄醇的环化反应，催化剂用量仅为0.05 mol%，可以较高的收率得到理想产物。为实现不对称反应，团队采用Piers硼烷处理手性磷酸制备了一种新型的手性硼磷酸盐，其中P=O的氧原子和硼原子分别作为Lewis碱中心和酸中心。

研究人员成功实现了对映选择性高的氢烷氧基化反应，得到了具有光学活性的1,3-二氢异苯并呋喃衍生物，收率为78-99%，ee值为60-97%，这一反应中O-H键的活化可能是通过硼磷酸盐物种发生的。

研究人员表示，烯烃分子内不对称氢烷氧基化是获取旋光性环醚的重要途径。

附：英文原文

Title: Asymmetric Intramolecular Hydroalkoxylation of 2-Vinylbenzyl Alcohols with Chiral Boro-Phosphates

Author: Caifang Han, Wei Meng, Xiangqing Feng, Haifeng Du

Issue&Volume: 2022-03-11

Abstract: Asymmetric intramolecular hydroalkoxylation of alkenes represents a very important approach to access optically active cyclic ethers. It was found that B(C  6  F  5  )  3  could catalyze the cyclization of 2-vinylbenzyl alcohols with only 0.05 mol % catalyst loading, affording the desired product in high yields. To accomplish the asymmetric reaction, a novel type of chiral boro-phosphates was developed by treating chiral phosphoric acid with Piers’ borane, in which the oxygen atom of P=O and the boron atom act as Lewis base and acid centers, respectively. A highly enantioselective hydroalkoxylation was successfully realized to give optically active 1,3-dihydroisobenzofuran derivatives in 78-99% yields with 60-97% ee’s, in which an activation of O-H bond of alcohols by the boro-phosphate species is hypothesized.

DOI: 10.1002/anie.202200100

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202200100