Institute of Chemistry, University of Campinas (UNICAMP), PO Box 6154, 13083-970, Campinas, Brazil.
Instituto Federal do Sertão Pernambucano, Estrada do Tamboril, 56200-000, Ouricuri, Brazil.
Chemistry. 2020 Jun 23;26(35):7808-7822. doi: 10.1002/chem.201905602. Epub 2020 Jun 3.
A 5,15-bis(1,1'-biphenyl)porphyrin-based molecular clip covalently connected to a ditopic aliphatic ester loop moiety yields a semi-rigid macrocycle with a well-defined cavity. The resulting macrocycle fits the structural requirements for the preparation of porphyrinates capable of promoting formation of C-C bonds. To demonstrate the usefulness of porphyrin-based macrocycles, an active-metal-template synthesis of rotaxanes through a redox non-innocent carbene transfer reaction is described. Coordination of Co ions into the porphyrin subunit followed by addition of appropriate monodentate nitrogen-based additives to function as axial ligands enables the radical carbene transfer reactions to styrene derivatives to occur exclusively through the cavity of the macrocycle to afford cyclopropane-linked rotaxanes in excellent 95 % yield. Investigation of the product distribution afforded from the rotaxane assembly reaction reveals how the redox cooperative action between the carbene species and the Co ions can be manipulated to gain control over the radical-type mechanism to favor the productive rotaxane forming process.
一种基于 5,15-双（1,1'-联苯）卟啉的分子夹与双位脂肪酯环部分共价连接，得到具有明确空腔的半刚性大环。所得大环符合制备能够促进 C-C 键形成的卟啉的结构要求。为了证明基于卟啉的大环的有用性，通过氧化还原非惰性卡宾转移反应描述了轮烷的活性金属模板合成。钴离子与卟啉亚基配位，然后加入适当的单齿氮基添加剂作为轴向配体，使得自由基卡宾转移反应能够仅通过大环的空腔与苯乙烯衍生物发生，以优异的 95%产率得到环丙烷连接的轮烷。对轮烷组装反应的产物分布的研究揭示了如何操纵卡宾物种和 Co 离子之间的氧化还原协同作用，以控制自由基型机制，有利于生产性轮烷形成过程。
