Organic Process Research & Development
Communication
kept out of the reaction tube, successfully avoiding problems in
product purification and additional waste generation.
Then experiments were performed to proven the concept.
First, we chose iodobenzene and aniline as the substrates under
the conditions we developed for aminocarbonylation of aryl
iodides; 55% of the desired amide can be produced with 2 equiv
of NEt3 as the base (Scheme 3, eq 1). A carbonylative Suzuki
(101 mg, 1 mmol), and DMF (2 mL). Next, formic acid (230
mg, 5 mmol) was added to the in-tube. Then the two tubes
were combined and sealed with a plastic septum. The whole
system was vacuumed through a Schlenk line and maintained
under an argon atmosphere. Concentrated sulfuric acid (0.28
mL, 5 mmol) was injected into the in-tube in three portions via
syringe. Finally, the reaction was immersed in an oil bath and
stirred at 100 °C for 24 h. Part of the sulfuric acid can be
injected during the reaction as well.
Scheme 3. Palladium-Catalyzed Carbonylations of
Iodobenzene
ASSOCIATED CONTENT
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S
* Supporting Information
The Supporting Information is available free of charge on the
General comments, analytic data, and NMR spectra of
AUTHOR INFORMATION
Corresponding Author
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ORCID
Notes
The authors declare no competing financial interest.
reaction between iodobenzene and phenyl boronic acid can be
realized as well (Scheme 3, eq 2). Then a carbonylative
Sonogashira reaction was tested in this in−ex tube and a 78%
yield of the corresponding alkynone can be produced without
any optimization (Scheme 3, eq 3). In these experiments, in
order to further prove the value of this new reactor, the
combination of formic acid and sulfuric acid (Morgan reaction)
was used for carbon monoxide generation.5
ACKNOWLEDGMENTS
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Analytic support from Dr. W. Baumann, Dr. C. Fisher, S.
Buchholz, S. Schareina, and Matthias Auer is gratefully
acknowledged. We also appreciate general support from
Professors Matthias Beller and Armin Borner in LIKAT.
̈
REFERENCES
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Additionally, reactions with SO2 and hydrogen were carried
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out as well (Scheme 4).6 Because of the high toxicity of SO2
Scheme 4. Reactions with SO2 and H2
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and the high flammability of H2, their manipulation and storage
require special attention. In our testings, SO2 and H2 were
produced from Na2SO3 and Zn, respectively, in the presence of
H2SO4. Delightfully, 58% and 82% of the corresponding
products can be formed, respectively.
In summary, in this short communication, an in−ex tube has
been designed and applied in gas related organic reactions. In
our testings, CO, SO2, and H2 are all applicable and gave the
corresponding products in moderate to good yields without any
optimization. We believe this tube will allow gas-reliant
reactions to be performed in an “efficient and easy” manner.
General Procedure. To the reaction tube were added
iodobenzene (0.5 mmol, 102 mg), aniline (1 mmol, 93 mg),
Pd(OAc)2 (5.6 mg, 25 μmol), PPh3 (13.1 mg, 50 μmol), Et3N
B
Org. Process Res. Dev. XXXX, XXX, XXX−XXX