Nano-Cu2O-catalyzed Glaser-type homo-coupling in H2O/TBAB
temperature, diluted with saturated sodium chloride solution
(10 ml) and extracted with diethyl ether (2 × 20 ml). The organic layer
was dried (Na2SO4) and transferred to a round-bottom flask. The
combined organic extracts were concentrated in vacuum, and the
resulting residue was purified by silica gel column chromatography
(hexane–ethyl acetate) to afford the desired products 2.
Acknowledgments
Scheme 2. Nano-Cu2O-catalyzed coupling reaction of 1-ethynylbenzene
and 1-ethynyl-4-methoxybenzene.
We are grateful to the Natural Science Foundation of Jiangxi Province
(no. 20151BAB203010) and the National Natural Science Foundation
of China (nos. 21563015 and 21502065) for financial support.
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Conclusions
We have firstly demonstrated a new and environmental method
for the synthesis of 1,3-diynes via homo-coupling of terminal
alkynes using a nano-Cu2O catalyst. Moreover, the system also
allowed the synthesis of unsymmetric 1,3-diynes by cross-
coupling of two different terminal alkynes. The results showed
that the efficient and environmentally friendly system is a good
extension of homo-coupling of terminal alkynes using copper
catalysis. Further studies are now ongoing to investigate the
possibility of applying this approach of using nano-Cu2O in
synthetic organic chemistry.
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General procedure for homo-coupling of
terminal alkynes
To a stirred solution of alkyne (0.6 mmol) in TBAB/H2O (1 g, 4:1), Cu2O
nanoparticles (0.06 mol) and NaOH (1.2 mmol) were added succes-
sively. The resulting mixture was then allowed to react at 80 °C in
O2. Progress of this reaction was monitored by TLC. After the reac-
tion was finished, the reaction mixture was cooled to room
Supporting information
Additional supporting information may be found in the online ver-
sion of this article at the publisher’s web site.
Appl. Organometal. Chem. (2016)
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