有机化学 ›› 2022, Vol. 42 ›› Issue (2): 580-589.DOI: 10.6023/cjoc202108029 上一篇    下一篇

研究论文

ent-Kaurene全碳骨架中AB环系的不对称合成

马文静a,*(), 朱礼志c, 章梦珣d, 李志成b,*()   

  1. a 滁州学院材料与化学工程学院 安徽滁州 239000
    b 香港浸会大学化学系 香港 999077
    c 深圳大学第一附属医院 深圳市第二人民医院 广东深圳 518037
    d 深圳大学药学院 广东深圳 518060
  • 收稿日期:2021-08-17 修回日期:2021-09-16 发布日期:2022-02-24
  • 通讯作者: 马文静, 李志成
  • 基金资助:
    安徽省高校自然科学一般项目(KJ2020B19); 滁州学院启动基金(2018qd06)

Asymmetric Synthesis of AB Rings in ent-Kaurene Carbon Framework

Wenjing Maa(), Lizhi Zhuc, Mengxun Zhangd, Chising Leeb()   

  1. a School of Material Science and Chemical Engineering, Chuzhou University, Chuzhou, Anhui 239000
    b Department of Chemistry, Hong Kong Baptist University, Hong Kong 999077
    c The First Affiliated Hospital of Shenzhen University, Shenzhen Second People’s Hospital, Shenzhen, Guangdong 518037
    d College of Pharmacy, Shenzhen University, Shenzhen, Guangdong 518060
  • Received:2021-08-17 Revised:2021-09-16 Published:2022-02-24
  • Contact: Wenjing Ma, Chising Lee
  • Supported by:
    Anhui University Natural Science Foundation-Funded Project(KJ2020B19); Chuzhou University Initial Funding(2018qd06)

本课题组前期利用多样性导向合成策略完成ent-kaurene天然产物Xerophilusin I、Neolaxiflorin L、Eriocalyxin B、15-epi-Enmelol全合成工作, 为完成该类天然产物的不对称合成, 对Horner-Wadsworth-Emmons反应进行了优化, 改善了反应的区域选择性, 在酸性条件下后处理, 将Z/E混合物转化为单一Z构型. 基于温和的酸性条件实现了单一构型的转化, 提出了氢键辅助的Michael加成/retro-Michael消除的机理猜想. 发展了Cu(OTf)2催化的不对称Diels-Alder反应: 以烯醇硅醚的双烯体3β-酮酸酯1为亲双烯体, 在噁唑啉为手性配体的条件下, 以65%的收率和>19∶1 dr值完成AB环的构建.

关键词: ent-kaurene天然产物, Horner-Wadsworth-Emmons反应, 区域选择性, 不对称Diels-Alder反应

The total synthesis of ent-kaurene natural products of Xerophilusin I, Neolaxiflorin L, Eriocalyxin B, 15-epi- Enmelol completed by diversity-oriented synthesis strategy. In this paper, the regioselectivity of Horner-Wadsworth-Emmons reaction was optimized, and a single Z configuration was transformed from Z/E mixture under acidic condition. Based on the conversion of a single configuration under mild acidic conditions, a mechanism for hydrogen bond-assisted Michael addition/retro-Michael elimination is proposed. The asymmetric Diels-Alder reaction with silylenol ether dienyl 3 and β-ketoate 1 as dienophile was developed. Using Cu(OTf)2 as Lewis acid and oxazoline as chiral ligand, AB-ring-skeleton was constructed with 65% yield and >19∶1 dr value.

Key words: ent-kaurane, Horner-Wadsworth-Emmons reaction, regioselectivity, asymmetric Diels-Alder reaction