State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China.
J Am Chem Soc. 2014 May 14;136(19):6900-3. doi: 10.1021/ja503117q. Epub 2014 May 5.
Stereocontrol in the synthesis of structurally complex molecules, especially those with all-carbon quaternary stereocenters, remains a challenge. Here, we reported the preparation of a class of tetracyclic cyclopenta-fused spiroindoline skeletons through Cu(II)-catalyzed intramolecular [3 + 2] annulation reactions of donor-acceptor cyclopropanes with indoles. Both cis- and trans-diastereomers of tetracyclic spiroindolines are accessed with high selectivities by altering the remote ester groups of cyclopropanes. The origins of this stereocontrol are identified using DFT calculations: attractive interactions between the ester group and arene favor the generation of the trans isomer, while the formation of the cis isomer is preferred when steric repulsions become predominant.
在结构复杂的分子，特别是具有全碳季碳中心的分子的合成中，立体控制仍然是一个挑战。在这里，我们报道了通过铜（II）催化给体-受体环丙烷与吲哚的分子内[3 + 2]环加成反应，制备了一类四环并环戊并螺吲哚骨架。通过改变环丙烷的远程酯基，可以高选择性地获得四环螺吲哚的顺式和反式非对映异构体。使用密度泛函理论（DFT）计算确定了这种立体控制的起源：酯基与芳环之间的吸引力相互作用有利于生成反式异构体，而当立体排斥作用占主导地位时，有利于生成顺式异构体。
