An N-heterocyclic carbene (NHC)-catalyzed atroposelective macrolactonization has been disclosed. This approach affords planar-chiral macrocycles in high yields with excellent enantioselectivities over a broad substrate scope. Controlled experiments suggest that the enantioselectivity might arise from the cation–n interaction between the acyl azolium and the electron-rich moiety in the substrate. This
已经公开了N-杂环卡宾(NHC)催化的阻转选择性大内
酯化。这种方
法能够以高产率提供平面手性大环化合物,并在广泛的底物范围内具有优异的对映选择性。对照实验表明,对映选择性可能源于酰基唑鎓与底物中富电子部分之间的阳离子-n相互作用。该机制得到了密度泛函理论计算的支持,这也表明了稳定过渡态中重要的 π-π 相互作用。