复旦大学蔡泉团队报道了通过2-吡喃酮与茚的催化不对称反电子需求Diels–Alder反应完成头孢烷内酯A和B的全合成。相关研究成果发表在2021年10月20日出版的国际学术期刊《德国应用化学》。

反电子需求Diels–Alder（IEDDA）反应可以补充六元碳环合成中传统的正常电子需求Diels–Alder反应。然而，催化不对称全碳基IEDDA反应尚不发达。

该文中，研究人员公开了使用缺电子3-羧基-2-吡喃酮和电子无偏茚作为反应物的铜催化不对称IEDDA反应。该方法能够快速且对映体选择性地构建广泛的六氢芴桥联内酯支架。利用该方法，完成了头孢烷内酯A和B的不对称全合成。

附：英文原文

Title: Catalytic Asymmetric Inverse-Electron-Demand Diels–Alder Reactions of 2-Pyrones with Indenes: Total Syntheses of Cephanolides A and B

Author: Quan Cai, Yang Lu, Meng-Meng Xu, Zhi-Mao Zhang, Junliang Zhang

Issue&Volume: 2021-10-20

Abstract: An inverse-electron-demand Diels–Alder (IEDDA) reaction could complement the conventional normal-electron-demand Diels–Alder reaction in the synthesis of six-membered carbocycles. However, catalytic asymmetric all-carbon-based IEDDA reactions are underdeveloped. Herein, we disclosed a copper-catalyzed asymmetric IEDDA reaction using electron-deficient 3-carboalkoxyl-2-pyrones and electronically unbiased indenes as reactants. This method enables the rapid and enantioselective construction of a wide range of hexahydrofluorenyl bridged-lactone scaffolds. Using this method, the asymmetric total syntheses of cephanolides A and B were accomplished.

DOI: 10.1002/anie.202112223

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202112223