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Evolution of Late Transition‐Metal‐Catalyzed Intermolecular Reductive Coupling Reaction of [60]Fullerene and N ‐Sulfonylaldimines: Competing Formation of Hydrobenzylated [60]Fullerenes and 1,2‐Dihydrofullerene
Author(s) -
Rajeshkumar Venkatachalam,
Chuang ShihChing
Publication year - 2012
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201200055
Subject(s) - chemistry , reductive elimination , fullerene , catalysis , coupling reaction , fullerene chemistry , rhodium , transition metal , photochemistry , oxidative addition , medicinal chemistry , organic chemistry
A system based on late transition‐metal halides, phosphanes, water, and reducing agents in 1,2‐dichlorobenzene can efficiently catalyze the intermolecular reductive coupling of [60]fullerene with N ‐sulfonylaldimines to afford novel 1,2‐hydrobenzylated [60]fullerene derivatives. We found that both group VII B metals (cobalt, rhodium, iridium) and group VIII B metals (nickel, palladium, platinum) perform this coupling reaction. A control experiment in the absence of aldimines produced C 60 H 2 , which showed that the reaction might proceed via a [60]fullerene metal complex [M(η 2 ‐C 60 )(ligand)]. An isotope labeling experiment with D 2 O as deuterium source resulted in deuterioaryzilation with deuterium bonded to the sp 3 ‐carbon of C 60 , providing evidence of a five‐membered azametallacycle intermediate. Evaluation of the scope of reductive coupling reaction with versatile aldimines gave access to the hydroaryzilation products. All the reductive coupling products were completely characterized by IR and NMR spectroscopy and ESI mass spectrometry. A possible reaction mechanism based on these results is proposed. This discovery of the formation of reductive coupling compounds and metal‐catalyzed formation of C 60 H 2 are both new to metal catalysis and fullerene chemistry.