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Olefin Cyclopropanation by Radical Carbene Transfer Reactions Promoted by Cobalt(II)/Porphyrinates: Active‐Metal‐Template Synthesis of [2]Rotaxanes
Author(s) -
Alcântara Arthur F. P.,
Fontana Liniquer A.,
Rigolin Vitor H.,
Andrade Yuri F. S.,
Ribeiro Marcos A.,
Barros Wdeson P.,
Ornelas Catia,
Megiatto Jackson D.
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201803934
Subject(s) - cyclopropanation , olefin fiber , cobalt , carbene , chemistry , metal , catalysis , photochemistry , combinatorial chemistry , polymer chemistry , organic chemistry
A Co II /porphyrinate‐based macrocycle in the presence of a 3,5‐diphenylpyridine axial ligand functions as an endotopic ligand to direct the assembly of [2]rotaxanes from diazo and styrene half‐threads, by radical‐carbene‐transfer reactions, in excellent 95 % yield. The method reported herein applies the active‐metal‐template strategy to include radical‐type activation of ligands by the metal‐template ion during the organometallic process which ultimately yields the mechanical bond. A careful quantitative analysis of the product distribution afforded from the rotaxane self‐assembly reaction shows that the Co II /porphyrinate subunit is still active after formation of the mechanical bond and, upon coordination of an additional diazo half‐thread derivative, promotes a novel intercomponent C−H insertion reaction to yield a new rotaxane‐like species. This unexpected intercomponent C−H insertion illustrates the distinct reactivity brought to the Co II /porphyrinate catalyst by the mechanical bond.