Dehydrogenation of D-glycals by palladium supported on activated charcoal under ethylene atmosphere: Synthesis of 1,5-anhydrohex-1-en-3-uloses

Article abstract of DOI:10.1055/s-1999-3602

Dehydrogenation reactions of D-glucal, D-galactal and L-rhamnal by palladium-on-charcoal under an ethylene atmosphere proceeded effectively to afford 1,5-anhydrohex-1-en-3-uloses in high yield.

Full text of DOI:10.1055/s-1999-3602

Evaluation Only. Created with Aspose.PDF. Copyright 2002-2021 Aspose Pty Ltd.
SHORT PAPER
1869
Dehydrogenation of D-Glycals by Palladium Supported on Activated Charcoal
under Ethylene Atmosphere: Synthesis of 1,5-Anhydrohex-1-en-3-uloses
Masahiko Hayashi*, Kanako Yamada, Shuzo Nakayama
Department of Chemistry, Faculty of Science, Yamaguchi University, Yamaguchi 753-8512, Japan
E-mail: hayashi@po.cc.yamaguchi-u.ac.jp
Received 17 June 1999; revised 14 July 1999
reaction using palladium-on-charcoal under an ethylene
Abstract: Dehydrogenation reactions of D-glucal, D-galactal and L-
atmosphere.
rhamnal by palladium-on-charcoal under an ethylene atmosphere
proceeded effectively to afford 1,5-anhydrohex-1-en-3-uloses in
high yield.
OH
O
OH
O
R2
OH
R2
R1
Key words: dehydrogenation, palladium, ethylene, glucal, ulose
5% Pd/C
CH2=CH2
CH3CN
R1
O
It has been known that dehydrogenative aromatizations of
hydroaromatic compounds are affected by catalytic
amounts of palladium supported on activated charcoal.1
However, these reactions are not always synthetically use-
ful, because these dehydrogenations require high temper-
atures (250–350 °C) and often cause the undesired
elimination of some functional groups. Other than these
examples, some dehydrogenation reactions using palladi-
um/charcoal catalyst have been reported. Kim and Choi
reported palladium-catalyzed dehydrogenation of a-hy-
drazinonitriles using cyclopentene which led to the forma-
tion of hydrazonoyl cyanides.2 As for dehydrogenation of
alcohols, Herz et al. found the conversion of an allylic al-
cohol in a sesquiterpene to the corresponding enone, how-
ever, they reported that the yield of the enone was only 5–
6% and that a large amount of starting material was recov-
ered.3
1: R1 = OH, R2 = H
3: R1 = H, R2 = OH
2: R1 = OH, R2 = H
4: R1 = H, R2 = OH
HO
O
HO
O
5% Pd/C
Me
Me
OH
CH2=CH2
CH3CN
O
5
6
Scheme
In the above Pd(OAc)2-catalyzed dehydrogenation, we
found that the black palladium precipitate which was
formed by the reaction of D-glucal with Pd(OAc)2 also
worked as an effective catalyst.9 Furthermore, in the case
of the ethylene system, the use of palladium precipitate
was more effective than the use of Pd(OAc)2. These re-
sults prompted us to examine the structure and catalytic
activity of this palladium precipitate. During the study
along this course, we discovered that palladium on acti-
vated charcoal also had catalytic activity for the dehydro-
genation of D-glucal under an ethylene atmosphere
(Scheme). That is, the treatment of D-glucal with a cata-
lytic amount of 10 weight% of 5% Pd/C (Pd, 0.5 weight%
per substrate) in acetonitrile at 50 °C for 42 hours afforded
1,5-anhydrohex-1-en-3-uloses (2) in 97% yield. The
amount of hydrogenated product, 2-deoxy-1,5-anhydro-
D-glucitol formed was less than 3%. On the other hand,
the reaction in the absence of ethylene gave the mixture of
oxidation product, 1,5-anhydrohex-1-en-3-ulose (2) and
hydrogenated product, in a ratio of 42:58 in 92% com-
bined yield. D-Galactal (3) and L-rhamnal (5) were also
converted into the corresponding enone 4 and 6 in 96 and
83% yield, respectively by treatment with a small amount
of Pd/C (Pd: 0.5 weight% per substrate). The obtained re-
sults are summarized in the Table. The role of ethylene is
crucial to realize the smooth reaction. The use of vinyl ac-
etate as a hydrogen acceptor did not work well in this Pd/
C catalyzed reaction. This result was in contrast with the
one of the Pd(OAc)2 system. Namely, in the case of
Pd(OAc)2, the use of vinyl acetate exhibited higher reac-
Hexenuloses have played an important role in carbohy-
drate synthesis.4 Among these, 1,5-anhydrohex-1-en-3-
ulose derivatives are of particular interest, because the
1,4-addition allows carbon–carbon bond formation at the
anomeric center which leads to the formation of 2-deoxy-
C-glycosides.5,6 One general method for incorporating the
a,b-unsaturated moiety is the oxidation of allylic alcohols.
Various stoichiometric oxidants such as chromium, man-
ganese, and palladium salts have been widely used for this
purpose,7,8 however, they are sometimes toxic and the use
of these reagents induces hazardous problems. The use of
expensive palladium compounds on a stoichiometric basis
cannot become a truly useful synthetic method. Therefore,
the development of a catalytic process has been strongly
desired. We recently reported the hydrogen transfer reac-
tion of the allylic alcohol in D-glucal (1) by using a cata-
lytic amount of palladium acetate [Pd(OAc)2] under an
ethylene atmosphere9 or in the presence of vinyl acetate,10
which leads to the facile synthesis of 1,5-anhydrohex-1-
en-3-uloses. All reactions above were initiated by the ac-
tion of Pd(II) species. Here we would like to report the
first examples of very mild and efficient dehydrogenation
Synthesis 1999, No. 11, 1869–1871 ISSN 0039-7881 © Thieme Stuttgart · New York

Evaluation Only. Created with Aspose.PDF. Copyright 2002-2021 Aspose Pty Ltd.
1870
M. Hayashi et al.
SHORT PAPER
20
[a]D30+282 (c= 0.5, H2O) [Lit.7 [a]D +297.5 (c= 1, H2O), Lit.12
Table Catalytic Oxidation of D-Glycals (1,3,5) by Pd/Ca
[a]D20 +283 (c= 0.8, H2O)].
IR (KBr) :n= 3350, 1660, 1605, 1420, 1280, 1120, 1040, 850 cm-1.
Entry Glycal Alkene
Temp (°C) Time (h) Yield(%)of
Productb
1H NMR (CDCl3, 400 MHz) :d= 1.6 (br s, 1H), 2.1 (br s, 1H), 4.03
(dd, J = 9.9 Hz, J = 3.6 Hz, 1H), 4.12 (dd, J = 9.9 Hz, J = 2.6 Hz,
1H), 4.20 (ddd, J = 11.8 Hz, J = 3.6 Hz, J = 2.6 Hz, 1H), 4.36 (d,
J = 11.8 Hz, 1H), 5.50 (d, J = 5.8 Hz, 1H), 7.43 (d, J = 5.8 Hz, 1H).
13C NMR (CD3OD) :d= 61.9, 69.2, 85.1, 105.1, 165.6, 197.2. Anal.
Calcd for C6H8O4: C, 50.00; H, 5.59. Found: C, 49.76; H, 5.66.
1
2
3
4c
5
6
1
1
3
3
5
5
none
ethylene
none
ethylene
none
ethylene
50
50
50
50
50
50
20
42
43
7
19
19
2, 38 (54)
2, 97 (3)
4, 46 (35)
4, 96 (3)
6, 45 (39)
6, 83 (8)
a All reactions were carried out using 10 weight% of 5% Pd/C in
CH3CN unless otherwise noted.
1,5-Anhydro-2-deoxy-D-threo-hex-1-en-3-ulose (5)
In a dry Schlenk tube were placed D-glucal (108 mg, 0.74 mmol)
and CH3CN (2 mL). To this was added 10% Pd/C (10.6 mg) under
an ethylene atmosphere and the mixture was stirred at 50 °C for 7 h
under an ethylene atmosphere. The black palladium solid was fil-
tered through a small amount of Celite, and the filtrate was concen-
trated. Purification by silica gel column chromatography using
EtOAc as eluent afforded 5 as a colorless oil; yield: 102 mg (96%);
Rf :0.33 (EtOAc); [a]D30 +170.0 (c 0.5, H2O) [Lit.7 [a]D20 +54 (c= 1,
H2O)].
IR (neat) :n= 3400, 1670, 1590 cm-1.
1H NMR (CDCl3, 400 MHz): d= 2.2 (br s, 1H), 3.8 (br s, 1H), 4.00
(d, J = 5.3 Hz, 2H), 4.56 (d, J = 6.3 Hz, 1H), 4.77 (dt, J = 6.3 Hz,
J = 5.3 Hz, 1H), 5.45 (d, J = 6.0 Hz, 1H), 7.35 (d, J = 6.0 Hz, 1H).
b Isolated yield of uloses after silica gel column chromatography. The
value in parenthesis indicates the isolated yield of the hydrogenated
product of glycals.
c 10% Pd/C was used.
tivity than the use of ethylene as a hydrogen acceptor. In
the Pd/C–ethylene system, ethylene would help to remove
hydrogen from the active surface of the catalyst, which fa-
cilitates the efficient conversion. The present method is
advantageous over the reported “palladium precipitate-
ethylene” method9 from the standpoint of availability of
the catalyst. Furthermore, in the Pd/C–ethylene system, a
smaller amount of palladium (Pd: 0.5 weight% per sub-
strate) is required for the reaction to proceed effectively
compared to the Pd(OAc)2-vinyl acetate system.
13C NMR (CD3OD):d= 60.3, 70.0, 84.1, 105.3, 165.0, 194.0.
Anal. Calcd for C6H8O4: C, 50.00; H, 5.59. Found: C, 49.75; H,
5.83.
1,5-Anhydro-2,6-dideoxy-L-erythro-hex-1-en-3-ulose (8)
In conclusion, we present the novel and efficient Pd/C–
ethylene system for the dehydrogenation reaction of D-
glycals, which leads to the facile synthesis of 1,5-anhy-
drohex-1-en-3-uloses.11
In a dry Schlenk tube were placed D-glucal (146 mg, 1.12 mmol)
and CH3CN (2 mL). To this was added 5% Pd/C (15.4 mg) under an
ethylene atmosphere and the mixture was stirred at 50 °C for 19 h
under an ethylene atmosphere. The black palladium solid was fil-
tered through a small amount of Celite, and the filtrate was concen-
trated. Purification by silica gel column chromatography using
EtOAc as eluent afforded 8 as colorless crystals; yield: 120 mg
(83%); Rf : 0.70 (hexane/EtOAc 1:1); mp 84–86 °C (Lit.7 mp 92–
1
All mps are uncorrected. H NMR spectra were recorded on a
BRUKER AVANCE 400S at 400 MHz with TMS used as an inter-
nal standard. The chemical shifts are reported in ppm on d scale
downfield from TMS, and signal patterns are indicated as follows:
s, singlet; d, doublet; t, triplet; m, multiplet; br, broad peak. 13C
NMR spectra were recorded on a BRUKER NMR spectrometer at
100.6 MHz. The chemical shifts are reported in ppm with CHCl3 d
(77.0 ppm) or TMS as internal standard. IR spectra were measured
on Nicolet Impact 410. Optical rotations were measured by SEPA-
300 (HORIBA) in solution in a 1-dm cell. Elemental analyses were
performed on Yanaco CHN CORDER MT-5. Preparative column
chromatography was carried out on a Fuji-Davison BW-820 or
Wacogel-300 column. TLC: Foil plates, silica gel 60 F254 (Merck;
layer thickness 0.2 mm). CH3CN was distilled from CaH2. D-Glucal
(1,5-anhydro-2-deoxy-D-arabino-hex-1-enitol), tri-O-acetyl-D-ga-
lactal, and 3,4-di-O-acetyl-L-rhamnal (3,4-di-O-acetyl-6-deoxy-L-
glucal) were purchased from Aldrich. D-Galactal and L-rhamnal
were prepared according to the reported procedure.7 Pd/C was pur-
chased from Wako and used without further purification.
93 °C, Lit.13 mp 86 °C); [a]D30 –244.6 (c= 1, CH3OH) [Lit.7 [a]D
20
–239 (c= 1, CH3OH), Lit.13 [a]D20 –288 (c= 1.3, CH3OH)].
IR (KBr) :n= 3404, 3104, 2916, 2354, 1675, 1600, 1408, 1258,
1204, 1129, 1058, 1038, 863, 821 cm-1.
1H NMR (CDCl3, 400 MHz):d= 1.58 (d, J = 6.2 Hz, 3H), 3.54 (br s,
1H), 3.98 (d, J = 13.0 Hz, 1H), 4.20 (dq, J = 6.2 Hz, J = 13.0 Hz,
1H), 5.60 (d, J = 5.8 Hz, 1H), 7.40 (d, J = 5.8 Hz, 1H).
13C NMR (CDCl3) :d= 17.5, 20.5, 73.1, 77.2, 105.1, 162.9, 169.4,
188.3.
Anal. Calcd for C6H8O3◊1/16 H2O: C, 55.76; H, 6.34. Found: C,
55.73; H, 6.34.
Acknowledgement
Support from Monbusho (Grant-in-Aid for Scientific Research on
Priority Areas, No. 706: Dynamic Control of Stereochemistry) is
gratefully acknowledged.
1,5-Anhydro-2-deoxy-D-erythro-hex-1-en-3-ulose (2)
In a dry Schlenk tube were placed D-glucal (168 mg, 1.15 mmol)
and CH3CN (2 mL). To this was added 5% Pd/C (17.1 mg) under an
ethylene atmosphere and the mixture was stirred at 50 °C for 42 h
under an ethylene atmosphere. The black palladium solid was fil-
tered through a small amount of Celite and the filtrate was concen-
trated. Purification by silica gel column chromatography using
EtOAc as eluent afforded 2 as colorless needles; yield: 161 mg
(97%); Rf: 0.39 (EtOAc); mp 85–87 °C [Lit.7 mp 87–88 °C);
References
(1) (a) Fu, P. P.; Harvey, R. G. Chem. Rev. 1978, 78, 317.
(b) Hudlicky, M. Oxidations in Organic Chemistry; ACS
Monograph 186; American Chemical Society: Washington,
DC, 1990; chapter 2, and references cited therein.
(2) Kim, Y. H.; Choi, J. Y. Tetrahedron Lett. 1996, 37, 8771.
Synthesis 1999, No. 11, 1869–1871 ISSN 0039-7881 © Thieme Stuttgart · New York

Evaluation Only. Created with Aspose.PDF. Copyright 2002-2021 Aspose Pty Ltd.
SHORT PAPER
Dehydrogenation of D-Glycals by Palladium Supported on Activated Charcoal
1871
(3) Herz, W.; Subramaniam, P. S.; Geissman, T. A. J. Org. Chem.
1968, 33, 3743.
(10) Hayashi, M.; Yamada, K.; Arikita, O. Tetrahedron 1999, 55,
8331.
(4) Holder, N. L. Chem. Rev. 1982, 82, 287.
(5) Tatsuta, K.; Hayakawa, J.; Tatsuzawa, Y. Bull. Chem. Soc.
Jpn. 1989, 62, 490.
(6) Benhaddou, R.; Czernecki, S.; Ville, G. J. Org. Chem. 1992,
57, 4612.
(11) The reaction of 2-cyclohexen-1-ol with 20 weight% of 5% Pd/
C (Pd, 1 weight% per substrate) in CH3CN at 50 °C for 3 h
under ethylene atmosphere afforded phenol, cyclohexanone,
and cyclohexanol in 45, 30, and 25% yield, respectively.
(12) Tronchet, J. M. J.; Tronchet, J.; Birkhauser, A. Helv. Chim.
Acta 1970, 53, 1489.
(7) Czernecki, S.; Vijayakumaran, K.; Ville, G. J. Org. Chem.
1986, 51, 5472.
(13) Paulsen, H.; Bünsch, H. Chem. Ber. 1978, 111, 3484.
(8) Bellosta, V.; Benhaddou, R.; Czernecki, S. Synlett 1993, 861.
(9) Hayashi, M.; Yamada, K.; Arikita, O. Tetrahedron Lett. 1999,
40, 1729.
Article Identifier:
1437-210X,E;1999,0,11,1869,1871,ftx,en;F03799SS.pdf
Synthesis 1999, No. 11, 1869–1871 ISSN 0039-7881 © Thieme Stuttgart · New York