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Insights into the Mechanism of the Ruthenium–Porphyrin‐Catalysed Allylic Amination of Olefins by Aryl Azides
Author(s) -
Intrieri Daniela,
Caselli Alessandro,
Ragaini Fabio,
Macchi Piero,
Casati Nicola,
Gallo Emma
Publication year - 2012
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201100763
Subject(s) - chemistry , nitrene , ruthenium , amination , allylic rearrangement , aryl , catalysis , porphyrin , azide , catalytic cycle , olefin fiber , tetraphenylporphyrin , photochemistry , combinatorial chemistry , reaction mechanism , medicinal chemistry , organic chemistry , alkyl
This paper describes the synthesis of allylic amines by aryl azides (ArN 3 ) catalysed by [Ru(TPP)CO] (TPP = dianion of tetraphenylporphyrin). The employment of aryl azides renders the methodology sustainable as the formation of molecular nitrogen is the only stoichiometric byproduct. The isolation of catalytic intermediates and spectroscopic and kinetic studies revealed interesting information about the reaction mechanism, which could improve its catalytic efficiency in future research. An important result is the X‐ray characterisation of [Ru(TPP)(ArN) 2 ] [Ar = 3,5‐(CF 3 ) 2 C 6 H 3 ], which is active in both stoichiometric and catalytic nitrene transfer reactions. The proposed involvement of carbonyl‐monoimido‐ruthenium porphyrin complexes in the catalytic cycle is also derived from our kinetic and experimental results. All the data indicate the coexistence of two mechanisms, where the electronic nature of the engaged aryl azide and olefin concentration determine one mechanism or the other.