UPDATES
Hydrogen Self-Sufficient Arene Reduction to Cyclohexane Derivatives
tered and concentrated under vacuum to give the analytical-
ly pure cyclohexane product.
tive (entry 8). Furthermore, the coexisting reducible
functionalities, such as the alkene and benzylic alco-
hol functionalities of cinnamic acid (1j), stilbene (1k)
and benzhydrol (1l), were completely hydrogenated
to give the corresponding saturated cyclohexane de-
rivatives (entries 9–11).
Acknowledgements
During the reduction of 1a, the inside pressure in
the stainless steel sealed tube slightly increased up to
1.8 bar regardless of the distention of the enclosed gas
This work was partially supported by the Research Founda-
tion for Pharmaceutical Sciences for Y. S. and the Sasakawa
Scientific Research Grant for T. Y. Furthermore, we thank the
by heat [Eq. (1)].[9] Therefore, the Pt/C-catalyzed hy- N. E. Chemcat Corporation for the kind gift of 10% Pt/C.
drogen generation by the dehydrogenation of i-PrOH
proceeded quite gently and the resulting hydrogen
was smoothly consumed by the reduction of the arene
with the formation of acetone. Since the excess hydro-
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Experimental Section
General Procedure
A suspension of an arene (0.5 mmol), 10% Pt/C (5 mol%)
in i-PrOH (4 mL) and H2O (2 mL) in a 12-mL stainless steel
sealed tube was stirred at 1008C. After stirring for a specific
reaction time, the mixture was cooled to room temperature
and filtered using a membrane filter (Milipore, Millexꢁ-LH,
0.2 mm) to remove the catalysts. The filtrate was extracted
with Et2O (20 mL) and H2O (20 mL), and then the aqueous
layer was further extracted with Et2O (10 mL3). The com-
bined organic layers were dried over anhydrous MgSO4, fil-
Adv. Synth. Catal. 2015, 357, 3667 – 3670
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3669