研究室工作進展 May 25th, 2011
Iterative Dianion Relay Along the Ring: Formation of gem-Bis(trimethylsilyl) Cyclopentenones from 2,5-Bis(trimethylsilyl) Oxy-cyclopentadienyl Dianions and Acid Chlorides
Heng Li, Lantao Liu, Zitao Wang, Fei Zhao, Shaoguang Zhang, Wen-Xiong Zhang, and Zhenfeng Xi*
Chem. Eur. J.2011, online 20110525, DOI: 10.1002/chem.201100830
Dianionicrelay linchpins: A new type of anion relay linchpin for migrating silyl groups was developed to form the interesting gem-bis(trimethylsilyl) cyclopentenones containing a stable enol moiety. The dianion was relayed iteratively along the Cp ring with the exocyclic oxy anion as the posthouse. Furthermore, isolation and structural information of key intermediates were achieved to support the proposed mechanism.
背景介紹：
2009年，本研究室成功分離得到了雙锂試劑1,4-二锂-1,3-丁二烯與一氧化碳反應産生的雙锂氧代環戊二烯基雙負離子活性中間體（OCp）（Lantao Liu, Wen-Xiong Zhang, Chao Wang, Congyang Wang, and Zhenfeng Xi*, Isolation, Structural Characterization and Synthetic Application of Oxy-cyclopentadienyl Dianions, Angew. Chem. Int. Ed. 2009, 48, 8111）。該類雙負離子中間體代表一類全新雙負離子化合物，具有豐富的反應化學和用途。
在進一步的工作中，我們堅持本研究室“基于機理研究和活性中間體的合成化學”研究理念，發現2，5位三甲基矽基取代的OCp可以作為一種新型的“陰離子接力合成子”，其在酰氯的誘導下，可以發生陰離子接力的矽基遷移反應。在反應過程中，氧負離子作為一個“驿站”将矽基從2位接力到5位。我們同時對該矽遷移機理進行了深入研究，分離并表征了反應中産生的重要中間體的單晶結構。