Zhou Han-Qi, Gu Xing-Wei, Zhou Xiao-Hua, Li Li, Ye Fei, Yin Guan-Wu, Xu Zheng, Xu Li-Wen
Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University No. 2318, Yuhangtang Road Hangzhou 311121 P. R. China
State Key Laboratory for Oxo Synthesis and Selective Oxidation, Suzhou Research Institute and Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences P. R. China.
Chem Sci. 2021 Sep 20;12(41):13737-13743. doi: 10.1039/d1sc04558j. eCollection 2021 Oct 27.
Catalytic asymmetric variants for functional group transformations based on carbon-carbon bond activation still remain elusive. Herein we present an unprecedented palladium-catalyzed (3 + 2) spiro-annulation merging C(sp)-C(sp) σ bond activation and click desymmetrization to form synthetically versatile and value-added oxaspiro products. The operationally straightforward and enantioselective palladium-catalyzed atom-economic annulation process exploits a TADDOL-derived bulky P-ligand bearing a large cavity to control enantioselective spiro-annulation that converts cyclopropenones and cyclic 1,3-diketones into chiral oxaspiro cyclopentenone-lactone scaffolds with good diastereo- and enantio-selectivity. The click-like reaction is a successful methodology with a facile construction of two vicinal carbon quaternary stereocenters and can be used to deliver additional stereocenters during late-state functionalization for the synthesis of highly functionalized or more complex molecules.
基于碳-碳键活化的官能团转化的催化不对称变体仍然难以捉摸。在此，我们展示了一种前所未有的钯催化（3+2）螺环化反应，该反应将C（sp）-C（sp）σ键活化与点击去对称化相结合，以形成具有合成多功能性和高附加值的氧杂螺环产物。该操作简单且对映选择性的钯催化原子经济性环化过程利用了一种由TADDOL衍生的带有大空腔的大位阻P配体，以控制对映选择性螺环化反应，该反应将环丙烯酮和环状1,3-二酮转化为具有良好非对映和对映选择性的手性氧杂螺环环戊烯酮-内酯支架。这种类似点击反应的方法是一种成功的方法，能够轻松构建两个相邻的碳季立体中心，并且可用于在后期官能团化过程中引入额外的立体中心，以合成高度官能团化或更复杂的分子。
