TY - JOUR
T1 - Evolution of late transition-metal-catalyzed intermolecular reductive coupling reaction of [60]fullerene and N-sulfonylaldimines
T2 - Competing formation of hydrobenzylated [60]fullerenes and 1,2-dihydrofullerene
AU - Rajeshkumar, Venkatachalam
AU - Chuang, Shih-Ching
PY - 2012/7/1
Y1 - 2012/7/1
N2 - 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 60H 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 2O 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 60H 2 are both new to metal catalysis and fullerene chemistry. A system based on late transition-metal halides, phosphanes, water, and reducing agents in o-DCB can efficiently catalyze intermolecular reductive coupling between [60]fullerene and N-sulfonylaldimines to afford new 1,2-hydrobenzylated [60]fullerene derivatives. The reaction yields are moderate, due to the formation of C 60H 2 as a byproduct. A possible reaction mechanism is proposed.
AB - 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 60H 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 2O 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 60H 2 are both new to metal catalysis and fullerene chemistry. A system based on late transition-metal halides, phosphanes, water, and reducing agents in o-DCB can efficiently catalyze intermolecular reductive coupling between [60]fullerene and N-sulfonylaldimines to afford new 1,2-hydrobenzylated [60]fullerene derivatives. The reaction yields are moderate, due to the formation of C 60H 2 as a byproduct. A possible reaction mechanism is proposed.
KW - C-C coupling
KW - Fullerenes
KW - Reductive coupling
KW - Transition metals
UR - http://www.scopus.com/inward/record.url?scp=84863636107&partnerID=8YFLogxK
U2 - 10.1002/ejoc.201200055
DO - 10.1002/ejoc.201200055
M3 - Article
AN - SCOPUS:84863636107
SP - 3795
EP - 3805
JO - European Journal of Organic Chemistry
JF - European Journal of Organic Chemistry
SN - 1434-193X
IS - 20
ER -