化学学报 ›› 2017, Vol. 75 ›› Issue (8): 794-797.DOI: 10.6023/A17040144 上一篇    下一篇

研究通讯

铜催化苯乙烯不对称硼胺化反应

张涌灵a,b, 王敏a, 曹鹏a, 廖建a,b   

  1. a 中国科学院成都生物研究所 天然产物研究中心 成都 610041;
    b 中国科学院大学 北京 100049
  • 收稿日期:2017-04-12 出版日期:2017-08-15 发布日期:2017-05-09
  • 通讯作者: 廖建,E-mail:jliao@cib.ac.cn E-mail:jliao@cib.ac.cn
  • 基金资助:

    项目受国家自然科学基金(Nos.21472184,21572218和21402186)资助.

Copper-Catalyzed Enantioselective Aminoboration of Styrenes with Chiral Sulfoxide Phosphine Ligand

Zhang Yonglinga,b, Wang Mina, Cao Penga, Liao Jiana,b   

  1. a Natural Products Research Center, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041;
    b University of Chinese Academy of Sciences, Beijing 100049
  • Received:2017-04-12 Online:2017-08-15 Published:2017-05-09
  • Contact: 10.6023/A17040144 E-mail:jliao@cib.ac.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos.21472184,21572218 and 21402186).

报道了一种以手性亚砜膦配体/铜络合物为催化剂的苯乙烯不对称硼胺化反应,该方法以联硼酸频哪醇酯(pinB-Bpin)和亲电性胺试剂分别作为硼源和氮源,合成手性β-氨基烷基硼酯,该产物可方便地转化为有用的手性β-羟胺类化合物.

关键词: 铜催化, 手性亚砜膦配体, 苯乙烯, 不对称硼胺化, 手性β-羟胺

To date, copper catalysis has become an attractive approach to access multifunctional alkylborons through borylative coupling processes, many important protocols such as carboboration, stannylboration and aminoboration were developed. Among these methods, however, there is no report involving enantioselective aminoboration of simple styrene substrates, which can generate a class of useful chiral compounds. In this work, an enantioselective Cu-catalyzed aminoboration of styrenes by using a chiral sulfoxide-phosphine (SOP) ligand was developed, chiral β-aminoalkylboranes were obtained in satisfied yields and ee values, and these products can be readily converted to a class of valuable β-hydroxylalkylamines. A general procedure for the aminoboration of styrenes is as following:in glove box, CuCl (0.02 mmol), chiral sulfoxide phosphine L1 (0.022 mmol) and 2.0 mL of dried tetrahydrofuran were added into a flame-dried tube, the resolved solution was stirred for 30 min at room temperature, then bis(pinacolato)diboron (B2pin2) (0.3 mmol), t-BuOLi (0.6 mmol) and styrene (0.2 mmol) were added. The tube was taken out of the glove box and cooled to 0℃. Electrophilic amination reagent, O-benzoyl-N,N-dibenzylhydroxylamine (2a, 0.3 mmol), was dissolved in 1.0 mL of ethyl acetate and added to the mixture, the resolved mixture was stirred at 0℃ for 24 h. The crude product was filtered through a celite pad, concentrated and oxidized by NaBO3·4H2O. The mixture was extracted three times with ethyl acetate, concentrated and purified with silica gel chromatography to give the desired β-hydroxylalkylamines, the enantioselective excess of products were determined by chiral HPLC analysis. Broad substrate scope which related to steric and electronic effect were compatible in this catalysis under the standard conditions. To demonstrate the utility of this method, a gram scale experiment was performed and the desired product was obtained in 92% isolated yield and 90% ee. The benzyl group of products can be readily removed via a Pd/C-catalyzed hydrogenation process and the corresponding product with a free amino group in excellent yield (95%).

Key words: Cu-catalyzed, chiral sulfoxide phosphine, styrenes, enantioselective aminoboration, β-hydroxylalkylamines