Use of the composite material RuO2/BaTi4O9 as an environmentally benign solid catalyst for the oxidative cleavage of olefins

Article abstract of DOI:10.1055/s-2007-992378

Catalytic use of a composite material, RuO₂/BaTi ₄O₉, in combination with NaIO₄ in EtOAc-H ₂O has been shown to efficiently cleave alkenes, affording ketones, aldehydes and/or carboxylic acids in high yields. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-2007-992378

LETTER
3201
Use of the Composite Material RuO2/BaTi4O9 as an Environmentally Benign
Solid Catalyst for the Oxidative Cleavage of Olefins
R
uO –BaT
i
O
4 9 asiSolid
C
r
atalyst
f
o
or the
O
xida
s
h
a
ge of
O
lefin
i
s
Okumoto,* Kazuhiro Ohtsuka, Shinji Banjoya
2
Department of Life Science, Kurashiki University of Science and the Arts, 2640 Nishinoura, Tsurajima, Kurashiki, 712-8505 Japan
Fax +81(86)4401062; E-mail: okmt@chem.kusa.ac.jp
Received 11 September 2007
Ru did not show any distinct differences. Use of the 3%
Abstract: Catalytic use of a composite material, RuO2/BaTi4O9, in
reagent in lieu of the 1% reagent often improved the yield
and reaction time, especially for highly substituted ole-
combination with NaIO4 in EtOAc–H2O has been shown to effi-
ciently cleave alkenes, affording ketones, aldehydes and/or carbox-
fins. Use of 1% RuO2/BaTi4O9 (10 mg) was sufficient to
consume 1 mmol of the substrate. The turnover of Ru ex-
ceeded 1000, being markedly superior to the conventional
procedure.8 Previous methods were usually performed us-
ing 3–5 mol% of RuCl3 or RuO2 since some deterioration
of activity is unavoidable.3,8
ylic acids in high yields.
Key words: ruthenium, green chemistry, oxidation, cleavage, het-
erogeneous catalysis
Cleavage of carbon–carbon double bonds is a fundamen-
tal reaction utilized to generate carbonyl functional
groups such as with ketones, aldehydes and carboxylic ac-
ids. Besides ozonolysis, metal-catalyzed oxidation plays a
principal role particularly in delicate synthetic manipula-
tions.1 Although various metals have been used,2 rutheni-
um offers several advantages given its reasonable cost,
low toxicity and controllable reactivity.3 On the other
hand, use of heterogeneous catalytic systems offers ad-
vantages from an environmental aspect since the solid can
be readily separated, recovered and recycled.3 Although
use of immobilized Ru reagents has achieved promising
results,4 most of the immobilized Ru oxidants have been
employed in the oxidation of alcohols,5 and not in the
cleavage of double bonds.
Table 1 Oxidation of alkylidene group
O
cat. RuO2/BaTi4O9
NaIO4 (6 equiv)
EtOAc–H2O–buffer (pH 6.88)
R
R
1
2
Alkene 1
Cat. (% Ru)
Yield (%)
EtO2C
EtO2C
3
1
89
78
1a
O
3
1
84
79
1b
1c
Our interests concern the development of an operationally
benign catalyst for the cleavage of carbon–carbon double
bonds in the context of the synthesis of bioactive com-
pounds derived from sugars.6 A report7 detailing the prep-
aration of ceramics utilizing RuO2/BaTi4O9 prompted us
to examine its potential use as a heterogeneous oxidizing
agent of alkenes (Scheme 1).
O
O
3
81
TBSO
THPO
cat.
RuO2/BaTi4O9
R1
R1
R2
R1
H
R1
1d
1e
3
3
71
73
O
O
O
or
or
NaIO4
EtOAc–H2O
R2
HO
MeO
Scheme 1
Following the preparation of ceramics with variable Ru
content, 1%, 3% and 5%, we initially investigated oxida-
tive capacity in combination with typical co-oxidants. On
the basis of these preliminary experiments, NaIO4 was se-
lected as a reoxidant based on yield, catalyst turnover and
reaction time. The two reagents comprising 3% and 5%
MeO
Et
N
1f
3
3
80
93
MeO2C
Bn
N
1g
MeO2C
Ph
SYNLETT 2007, No. 20, pp 3201–3205
x
x
.x
x
.2
0
0
7
1h
3
88
Advanced online publication: 21.11.2007
DOI: 10.1055/s-2007-992378; Art ID: U08307ST
N
Ac
© Georg Thieme Verlag Stuttgart · New York

3202
H. Okumoto et al.
LETTER
The cleavage of 1,1-disubstituted alkenes 1 giving rise to employed. Predominant formation of the aldehydes 6 was
ketones 2 is summarized in Table 1. Treatment of 1 in an achieved as depicted for 5a and 5b, while the selectivity
aqueous medium resulted in formation of the expected decreased in the case of nitrogen-containing compounds
methyl ketones 2 in satisfactory yields. The oxidation 5c and 5d. Although Ru-mediated reactions have been de-
could be performed under very mild conditions without veloped that control the oxidation state of the olefin,9 pre-
any special techniques. When a buffer solution was added, venting oxidation at intermediary stages in the RuO2/
the acid-labile functional groups such as epoxide, TBS RuO4 redox system remains problematic.8 The common
and THP were tolerated under the reaction conditions. Ru oxidant is powerful enough to convert the aldehydes 6
Compounds containing nitrogen atoms have been report- into the final carboxylic acids 7. The choice of Ru content
ed to undergo Ru-mediated oxidation.3 Aniline and ben- with respect to BaTi4O9 was important in the selective
zylamine moieties are known to be particularly reactive. production of the aldehydes 6 and the carboxylic acids 7.
However, the present ceramic-catalyzed method worked In a similar manner to the results illustrated in Table 1, re-
efficiently in the cleavage of double bonds to produce actions with phenyl ether 5e and the nitrogen-containing
aminoketone compounds 2f, 2g and 2h in excellent yields. compounds 5c and 5d led to formation of 2-phenoxycar-
boxylic acid 7e and amino acid derivatives 7c and 7d, re-
The activity of the prepared ceramic reagents towards
spectively, notwithstanding the possibility of Ru-
double bond cleavage was mild compared with the con-
mediated oxidation.1,3,8
ventional RuO2/NaIO4 method.8 Although reaction with
the 3-substituted olefin 3 produced the corresponding ke- The oxidation process was then utilized with various sug-
tocarboxylic acid 4 in 61% yield after 21 hours ar derivatives.10 The oxidation proceeded cleanly and
(Scheme 2), the oxidation of tetrasubstituted olefin did stepwise to afford the aldehyde followed by the corre-
not proceed to any appreciable extent.
sponding carboxylic acid (Scheme 3). It was possible to
isolate the aldehyde in moderate yield by careful monitor-
ing of the reaction using TLC. For example, oxidation of
8 could be interrupted at two hours to afford the aldehyde
9 in 59% yield together with the carboxylic acid 10 in 27%
yield. In this case, strict control leading to exclusive for-
mation of the aldehyde 9 was not achieved even when 1%
RuO2/BaTi4O9 was used. When the reaction was contin-
ued for six hours, the carboxylic acid 10 was generated in
91% yield as the only product. A similar sugar derivative
11 prepared from D-arabinose underwent smooth oxida-
tion, and quantitative production of the acid 12 was
achieved in four hours. The other products 14, 16 and 18
contain an acetylated aldol moiety, which is considerably
labile to both acid- and base-driven elimination. Our pro-
3% RuO2/BaTi4O9,
NaIO4 (6 equiv)
O
CO2H
OAc
21 h
61%
OAc
3
4
Scheme 2 Oxidation of terpinyl acetate
Subsequent investigations dealt with the oxidative cleav-
age of terminal olefins 5 affording aldehydes 6 and/or car-
boxylic acids 7. The results are shown in Table 2.
The monosubstituted olefins 5 could readily be cleaved to
give the appropriate products depending on the conditions
Table 2 Cleavage of terminal olefins
cat. RuO2/BaTi4O9
CHO
COOH
+
R
R
R
NaIO4
5
6
7
EtOAc–H2O–buffer (pH 6.88)
Alkene 5
Cat. (% Ru)
NaIO4 (equiv)
Time (h)
Yield (%) of 6
Yield (%) of 7
1
3
4
6
21
21
98
–
–
87
AcO
OAc
5a
O
1
3
4
4
24
24
98
12
–
87
CO2Et
5b
5c
MeO2C
1
3
4
6
12
3
64
–
8
95
MeO2C
N
Boc
Ph
1
3
4
6
29
21
47
–
33
90
5d
5e
N
Boc
PhO
3
6
72
–
78
Synlett 2007, No. 20, 3201–3205 © Thieme Stuttgart · New York

LETTER
RuO2/BaTi4O9 as Solid Catalyst for the Oxidative Cleavage of Olefins
3203
In conclusion, the composite material RuO2/BaTi4O9 was
shown to act as an efficient and reusable oxidant.12 Fur-
ther experiments are in progress in an effort to develop
protocols under a variety of oxidation conditions that re-
flect environmentally friendly conditions such as the use
of oxygen in lieu of NaIO4, and avoiding the use of chem-
ical reoxidants.
O
O
3% RuO2/BaTi4O9
O
NaIO4 (6 equiv)
EtOAc–H2O–buffer (pH 6.88)
OAc
O
8
O
O
O
O
O
O
CHO
COOH
OAc
O
OAc O
Acknowledgment
9
10
27%
91%
2 h
6 h
59%
–
We are grateful to Professor Yoshihiro Kusano of Kurashiki Uni-
versity of Science and the Arts for preparation of the 1%, 3% and
5% RuO2–BaTi4O9 reagents and to Professor Masato Kakihana of
Tohoku University for suggesting preparation of the ceramics.
O
O
O
O
O
O
COOH
COOH
4 h
References and Notes
OAc
O
98%
11
OAc
O
12
14
(1) Backvall, J.-E. Modern Oxidation Methods; Wiley-VCH:
Weinheim, 2004.
OAc OAc
OAc OAc
AcO
(2) For recent works describing transition-metal-mediated
cleavage with Os reagent, see: (a) Ley, S. V.; Ramarao, C.;
Lee, A.; Ostergaard, N.; Smith, S. C.; Shirley, I. M. Org.
Lett. 2003, 5, 185. (b) Travis, B. R.; Narayan, R. S.; Borhan,
B. J. Am. Chem. Soc. 2002, 124, 3824. (c) With AuCl
reagent, see: Xing, D.; Guan, B.; Cai, G.; Fang, Z.; Yang, L.;
Shi, Z. Org. Lett. 2006, 8, 693.
(3) Murahashi, S.; Komiya, N. In Ruthenium in Organic
Synthesis; Murahashi, S., Ed.; Wiley-VCH: Weinheim,
2004, 65–69.
(4) For recent typical examples, see: (a)Kim, W.; Park, I.; Park,
J. Org. Lett. 2006, 8, 2543. (b) Zhan, B.; White, M. A.;
Sham, T.; Pincock, J. A.; Doucet, R.; Rao, K. V. R.;
Robertson, K. N.; Cameron, T. S. J. Am. Chem. Soc. 2003,
125, 2195. (c) Cheung, W.; Yu, W.; Yip, W.; Zhu, N.; Che,
C. J. Org. Chem. 2002, 67, 7716. (d) Yamaguchi, K.; Mori,
K.; Mizugaki, T.; Ebitani, K.; Kaneda, K. J. Am. Chem. Soc.
2000, 122, 7144; and references cited therein.
AcO
11 h
76%
OAc OAc
OAc OAc
13
O
O
O
O
O
O
O
20 h
79%
COOH
COOH
O
OAc
O
15
O
OAc
OAc
16
O
O
O
O
O
O
OAc
OAc
4 h
98%
OAc
17
18
Scheme 3 Oxidative cleavage of sugar derivatives
(5) For an excellent work detailing control of the oxidation stage
with immobilized Ru species, see: Ho, C.; Yu, W.; Che, C.
Angew. Chem. Int. Ed. 2004, 43, 3303.
(6) (a) Okumoto, H.; Katto, H. Synlett 2003, 1521.
(b) Fukusaki, F.; Takeno, S.; Takeshi Bamba, T.; Okumoto,
H.; Katto, H.; Kajiyama, S.; Kobayashi, A. Biosci.,
Biotechnol., Biochem. 2004, 68, 1988.
(7) Tada, M.; Yamashita, Y.; Petrykin, V.; Osada, M.; Yoshida,
K.; Kakihana, M. Chem. Mater. 2002, 14, 2845.
(8) Carlsen, P. H. J.; Katsuki, T.; Martin, V. S.; Sharpless, K. B.
J. Org. Chem. 1981, 46, 3936.
(9) For oxidation using RuCl3 leading to aldehyde, see:
(a) Yang, D.; Zhang, C. J. Org. Chem. 2001, 66, 4814. For
oxidation using RuCl3 leading to diol, see: (b) Tiwari, P.;
Misra, A. K. J. Org. Chem. 2006, 71, 2911. (c) Plietker, B.;
Niggemann, M. J. Org. Chem. 2005, 70, 2402. (d) Plietker,
B.; Niggemann, M. Org. Lett. 2003, 5, 3353. (e) For
oxidation using RuCl3 leading to acyloin, see: Plietker, B.
J. Org. Chem. 2004, 69, 8287.
(10) The sugar derivatives 8, 11 and 13 were prepared from D-
ribose, D-arabinose and D-xylose, respectively, according to
the literature, followed by usual acetylation: (a) Shing, T.
K. M.; Wong, W. F.; Ikeno, T.; Yamada, T. Org. Lett. 2007,
9, 207. (b) Lievens, S. C.; Molinski, T. F. J. Am. Chem. Soc.
2006, 128, 11764. (c) Prenner, R. H.; Binder, W. H.;
Schmid, W. Liebigs Ann. Chem. 1994, 73. (d) The acetate
15 was synthesized by reaction of the aldehyde 19 and allyl
Grignard reagent, followed by acetylation as illustrated in
tocol was shown to be effective in the presence of this sen-
sitive array of functional groups.11
Further experiments investigating the possibility of reus-
ing the ceramics were performed with the alkene 5a using
1% RuO2/BaTi4O9 and NaIO4 (4 equiv). After most of the
starting material 5a was consumed, the solid reagent was
removed by filtration and utilized again in another round
of catalysis. This process was repeated twice. The alde-
hyde 6a was isolated from each filtrate by the usual pro-
cedure. The yields in the second and third rounds of
catalysis decreased slightly to ca. 75%, with the reaction
taking longer to complete. An alternative strategy was
also employed as follows. When the first round of cataly-
sis was completed, the stirring was stopped and the super-
natant was removed by decantation to isolate the product.
To the remaining aqueous phase containing inorganic ma-
terials was added the requisite amount of NaIO4 followed
by an organic solution of the olefin 5a. The second round
of catalysis also generated the aldehyde 6a in ca. 75%
yield. These results indicate that although the reagent de-
teriorated somewhat, it remained active and could be re-
used without the use of any extraneous procedures.
Synlett 2007, No. 20, 3201–3205 © Thieme Stuttgart · New York

3204
H. Okumoto et al.
LETTER
156.1, 156.8, 204.0, 204.1.
OMe
2g: 1H NMR (300 MHz, CDCl3): d = 2.03 (s, 1.5 H), 2.06 (s,
1)
O
O
MgCl
1.5 H), 3.71 (s, 1.5 H), 3.77 (s, 1.5 H), 3.90 (s, 1 H), 3.99 (s,
D-xylose
15
1 H), 4.52 (s, 1 H), 4.54 (s, 1 H), 7.15–7.40 (m, 5 H). 13
C
O
2) Ac2O
PTSA, DMF
NMR (126 MHz): d = 26.6, 26.8, 51.0, 51.5, 52.9, 52.9, 55.4,
55.7, 127.4, 127.5, 128.0, 128.5, 128.5, 136.7, 156.8, 157.0,
203.5, 203.6.
19
O
O
Scheme 4
2h: 1H NMR (300 MHz, CDCl3): d = 1.90 (s, 1.5 H), 1.92 (s,
1.5 H), 2.15 (s, 1.5 H), 2.16 (s, 1.5 H), 4.43 (s, 1 H), 4.44 (s,
1 H), 7.25–7.50 (m, 5 H). 13C NMR (75 MHz, CDCl3): d =
21.8, 26.9, 59.1, 127.6, 127.9, 129.6, 143.3, 170.5, 202.3.
4: 1H NMR (500 MHz, CDCl3): d = 1.35–1.47 (m, 1 H), 1.44
(s, 3 H), 1.53 (s, 3 H), 1.82–1.90 (m, 1 H), 1.95 (s, 3 H), 2.16
(s, 3 H), 2.15–2.23 (m, 1 H), 2.31–2.37 (m, 1 H), 2.48–2.59
(m, 3 H). 13C NMR (126 MHz, CDCl3): d = 22.2, 22.3, 24.0,
24.3, 30.1, 35.0, 42.0, 43.9, 84.4, 170.3, 179.0, 208.3.
6a: 1H NMR (500 MHz, CDCl3): d = 1.80–2.02 (m, 2 H),
2.067 (s, 3 H), 2.071 (s, 3 H), 2.54 (t, J = 7.1 Hz, 2 H), 4.06
(dd, J = 6.1, 11.9 Hz, 1 H), 4.24 (dd, J = 3.7, 11.9 Hz, 1 H),
5.05–5.20 (m, 1 H), 9.77 (s, 1 H). 13C NMR (126 MHz,
CDCl3): d = 20.6, 20.8, 23.1, 39.4, 64.6, 70.5, 170.4, 170.6,
200.6.
Scheme 4. For preparation of the intermediate aldehyde 19,
see ref. 10a and: Calinaud, P.; Gelas, J. In Preparative
Carbohydrate Chemistry; Hanessian, S., Ed.; Marcel
Dekker: New York, 1996, p15. (e) The diacetonide 17 is
readily accessible from D-mannose: Shing, T. K. M.; Wong,
W. F.; Cheng, H. M.; Kwok, W. S.; So, K. H. Org. Lett.
2007, 9, 753.
(11) General Experimental Procedure: To a solution of olefin
(0.5 mmol) in EtOAc (3 mL), H2O (5 mL) and phosphate
buffer (pH 6.88, 1 mL) were added 3% RuO2/BaTi4O9 (10
mg) and then NaIO4 (3 mmol) at r.t. The reaction mixture
was stirred for the indicated times. Solids were filtered and
washed with H2O. Filtrates were extracted with EtOAc and
the organic layer was dried and concentrated. The residue
was then chromatographed on silica gel to give the product.
(12) 2a: 1H NMR (300 MHz, CDCl3): d = 0.85 (t, J = 7.6 Hz, 3
H), 1.25 (t, J = 7.2 Hz, 6 H), 2.05 (q, J = 7.6 Hz, 2 H), 2.17
(s, 3 H), 3.10 (s, 2 H), 4.19 (q, J = 7.0 Hz, 4 H). 13C NMR
(75 MHz, CDCl3): d = 8.8, 13.7, 26.2, 30.0, 45.2, 55.6, 61.1,
170.5, 204.9.
7a: 1H NMR (500 MHz, CDCl3): d = 1.90–2.00 (m, 2 H),
2.07 (s, 6 H), 2.43 (dt, J = 1.5, 7.6 Hz, 2 H), 4.06 (dd, J = 5.9,
11.9 Hz, 1 H), 4.25 (dd, J = 3.7, 11.9 Hz, 1 H), 5.09–5.20 (m,
1 H). 13C NMR (126 MHz, CDCl3): d = 20.7, 20.9, 25.8,
29.7, 64.7, 70.4, 170.6, 170.8, 178.1.
6b: 1H NMR (500 MHz, CDCl3): d = 1.27 (t, J = 7.0 Hz, 3
H), 1.52 (s, 3 H), 2.26 (s, 3 H), 2.90 (d, J = 17.7 Hz, 1 H),
3.00 (d, J = 17.7 Hz, 1 H), 4.22 (q, J = 7.0 Hz, 2 H), 9.71 (s,
1 H). 13C NMR (126 MHz, CDCl3): d = 13.8, 20.4, 26.0,
39.4, 48.5, 56.9, 61.9, 171.6, 199.1, 204.7.
2b: a mixture of separable diastereomers in a ratio of ca. 4:1.
1
Major product: H NMR (500 MHz, CDCl3): d = 1.04 (d,
J = 6.4 Hz, 3 H), 1.43 (ddd, J = 3.3, 13.1, 26.3 Hz, 1 H), 1.73
(ddd, J = 3.4, 13.1, 25.6 Hz, 1 H), 2.19 (s, 3 H), 2.08–2.25
(m, 2 H), 2.35–2.45 (m, 1 H), 2.45–2.52 (m, 2 H), 2.77–2.86
(m, 1 H). 13C NMR (126 MHz, CDCl3): d = 14.2, 27.7, 28.2,
34.5, 42.6, 44.5, 52.1, 208.1, 211.4. Minor product: 1H NMR
(500 MHz, CDCl3): d = 1.09 (d, J = 7.0 Hz, 3 H), 1.50–1.58
(m, 1 H), 1.91–2.10 (m, 3 H), 2.18 (s, 3 H), 2.30–2.42 (m, 2
H), 2.65 (ddd, J = 1.2, 6.1, 15.0 Hz, 1 H), 3.06–3.12 (m, 1
H). 13C NMR (126 MHz, CDCl3): d = 15.2, 24.8, 28.1, 30.9,
40.5, 44.2, 50.1, 209.2, 211.3.
7b: 1H NMR (500 MHz, CDCl3): d = 1.27 (t, J = 7.0 Hz, 3
H), 1.51 (br s, 3 H), 2.23 (br s, 3 H), 2.92 (br s, 2 H), 4.21 (q,
J = 7.0 Hz, 2 H), 9.5 (br, 1 H). 13C NMR (75 MHz, CDCl3):
d = 13.8, 39.4, 61.8, 171.6.
6c: 1H NMR (300 MHz, CDCl3): d = 1.42 (s, 4.5 H), 1.45 (s,
4.5 H), 2.85–3.25 (m, 2 H), 3.69 (s, 1.5 H), 3.71 (s, 1.5 H),
3.75 (s, 1.5 H), 3.76 (s, 1.5 H), 3.90–4.25 (m, 2 H), 4.45–4.52
(m, 0.5 H), 4.80–4.90 (m, 0.5 H), 9.56 (m, 0.5 H), 9.58 (s, 0.5
H). 13C NMR (75 MHz, CDCl3): d = 28.3, 35.5, 52.1, 57.4,
57.5, 58.6, 58.6, 58.7, 58.7, 81.9, 99.2, 157.8, 154.8, 170.7,
170.7, 170.8, 170.8, 171.5, 171.5, 171.6, 171.6, 171.6,
171.9, 199.0.
2c: 1H NMR (500 MHz CDCl3): d = 1.42 (s, 3 H), 2.00 (ddd,
J = 1.2, 11.0, 14.9 Hz, 1 H), 2.19 (s, 3 H), 2.25 (dd, J = 11.0,
18.0 Hz, 1 H), 2.51 (dt, J = 3.0, 14.9 Hz, 1 H), 2.63 (ddd,
J = 1.2, 4.9, 18.0 Hz, 1 H), 3.10–3.18 (m, 1 H), 3.48 (dd, J =
0.9, 3.0 Hz, 1 H). 13C NMR (126 MHz, CDCl3): d = 15.1,
25.8, 28.2, 37.5, 41.8, 59.0, 60.6, 203.8, 208.2.
7c: 1H NMR (500 MHz, CDCl3): d = 1.43 (s, 4.5 H), 1.44 (s,
4.5 H), 2.90–3.20 (m, 2 H), 3.69 (s, 1.5 H), 3.70 (s, 1.5 H),
3.75 (s, 1.5 H), 3.76 (s, 1.5 H), 3.95–4.11 (m, 1.5 H), 4.32 (d,
J = 18.4 Hz, 0.5 H), 4.53 (t, J = 6.4 Hz, 0.5 H), 4.80 (t, J =
6.4 Hz, 0.5 H), 6.35 (br, 1 H). 13C NMR (126 MHz, CDCl3):
d = 27.9, 28.1, 34.9, 35.8, 49.8, 50.4, 52.0, 52.6, 52.9, 57.1,
58.3, 60.4, 82.0, 82.2, 154.3, 170.9, 171.5, 171.7, 171.7,
173.5, 173.7.
2d: 1H NMR (500 MHz, CDCl3): d = –0.29 (s, 3 H), –0.10
(s, 3 H), 0.73 (s, 9 H), 2.03 (s, 3 H), 2.42 (dd, J = 4.3, 14.6
Hz, 1 H), 2.81 (dd, J = 8.8, 14.6 Hz, 1 H), 3.68 (s, 3 H), 5.00
(dd, J = 4.3, 8.8 Hz, 1 H), 6.74 (d, J = 8.3 Hz, 2 H), 7.14 (d,
J = 8.3 Hz, 2 H). 13C NMR (126 MHz, CDCl3): d = –5.3,
–4.7, 18.0, 25.7, 31.8, 54.4, 55.2, 71.6, 113.6, 126.9, 136.6,
158.8, 207.3.
6d: 1H NMR (500 MHz, CDCl3): d = 1.44 (s, 9 H), 4.33 (s,
2 H), 7.20–7.40 (m, 5 H), 9.70 (s, 1 H). 13C NMR (126
MHz): d = 28.2, 60.1, 81.5, 126.4, 128.9, 142.5, 198.1.
7d: 1H NMR (500 MHz, CDCl3): d = 1.42 (s, 9 H), 4.30 (s,
2 H), 6.00 (br, 1 H), 7.20–7.40 (m, 5 H). 13C NMR (126
MHz, CDCl3): d = 28.1, 52.2, 81.3, 126.3, 128.7, 142.5,
154.9, 175.2.
2e: 1H NMR (500 MHz, CDCl3): d = 1.40–1.80 (m, 6 H),
2.12, 2.20 (s, 3 H), 2.60–2.70 (m, 1 H), 3.00–3.10 (m, 1 H),
3.20–3.30 (m, 0.5 H), 3.40–3.60 (m, 1 H), 3.78 (s, 3 H),
3.70–3.90 (m, 0.5 H), 4.39, 4.84 (t, J = 3.3 Hz, 1 H), 5.01 (dd,
J = 4.6, 8.5 Hz, 0.5 H), 5.14 (dd, J = 4.9, 8.9 Hz, 0.5 H),
6.80–6.90 (m, 2 H), 7.25–7.35 (m, 2 H). 13C NMR (126
MHz, CDCl3): d = 19.1, 19.1, 25.2, 30.4, 31.0, 31.0, 51.4,
51.6, 55.0, 55.1, 61.9, 62.0, 72.7, 75.2, 94.5, 98.9, 113.5,
113.8, 127.4, 128.0, 132.7, 134.6, 158.7, 159.2, 206.6.
2f: 1H NMR (300 MHz, CDCl3): d = 1.10 (t, J = 7.05 Hz, 3
H), 2.15 (s, 3 H), 3.20–3.45 (m, 2 H), 3.65 (s, 1.5 H), 3.72 (s,
1.5 H), 3.98, 4.04 (s, 2 H). 13C NMR (126 MHz, CDCl3):
d = 12.9, 13.3, 26.5, 26.7, 42.8, 43.4, 52.5, 52.6, 56.3, 56.6,
7e: 1H NMR (300 MHz, CDCl3): d = 4.30–5.00 (br, 1 H),
4.68 (s, 2 H), 6.90–7.40 (m, 5 H). 13C NMR (75 MHz,
CDCl3): d = 64.8, 72.6, 114.7, 122.1, 129.6, 157.4. 174.3.
9: 1H NMR (500 MHz, CDCl3): d = 1.35 (s, 3 H), 1.40 (s, 9
H), 2.11 (s, 3 H), 2.65–2.82 (m, 2 H), 3.87–3.94 (m, 2 H),
4.05–4.09 (m, 1 H), 4.25–4.30 (m, 1 H), 4.48–4.54 (m, 1 H),
5.16–5.21 (m, 1 H), 9.81 (s, 1 H). 13C NMR (126 MHz,
CDCl3): d = 20.9, 25.3, 26.4, 26.7, 27.1, 47.0, 66.1, 71.7,
Synlett 2007, No. 20, 3201–3205 © Thieme Stuttgart · New York

LETTER
72.4, 74.0, 79.5, 109.6, 110.1, 170.0, 199.4.
RuO2/BaTi4O9 as Solid Catalyst for the Oxidative Cleavage of Olefins
3205
H). 13C NMR (126 MHz, CDCl3): d = 20.5, 20.5, 20.6, 20.6,
20.7, 35.0, 61.8, 67.8, 68.9, 69.0, 70.4, 169.8, 170.0, 170.0,
170.2, 170.5, 173.7.
10: 1H NMR (500 MHz, CDCl3): d = 1.35 (s, 3 H), 1.40 (s, 9
H), 2.11 (s, 3 H), 2.63 (dd, J = 8.5, 16.1 Hz, 1 H), 2.76 (dd,
J = 3.5, 16.1 Hz, 1 H), 3.88–3.96 (m, 2 H), 4.08 (dd, J = 6.4,
8.3 Hz, 1 H), 4.29 (dd, J = 6.4, 11.9 Hz, 1 H), 4.45 (dt, J =
3.6, 8.3 Hz, 1 H), 5.22 (t, J = 5.0 Hz, 1 H), 5.90–6.20 (br, 1
H). 13C NMR (126 MHz, CDCl3): d = 21.1, 25.5, 26.5, 27.0,
27.3, 38.9, 66.2, 72.0, 74.1, 74.3, 79.5, 109.8, 110.4, 170.3,
175.6.
16: 2:1 mixture of diastereomers. 1H NMR (500 MHz,
CDCl3): d = 1.33, 1.36, 1.37, 1.38 (s, 12 H), 2.03, 2.04 (s, 3
H), 2.60–2.85 (m, 2 H), 3.75–3.93 (m, 2 H), 3.96–4.20 (m, 3
H), 5.25–5.40 (m, 1 H), 6.50 (br, 1 H). 13C NMR (126 MHz,
CDCl3): d = 20.8, 20.9, 25.4, 25.4, 26.0, 26.1, 26.6, 26.9,
27.0, 27.0, 35.4, 35.9, 65.5, 65.6, 67.5, 70.3, 74.6, 75.4, 76.1,
77.5, 77.6, 78.4, 109.8, 109.8, 110.0, 110.5, 170.3, 170.4,
174.8, 175.0.
12: 1H NMR (500 MHz, CDCl3): d = 1.36 (s, 3 H), 1.40 (s, 6
H), 1.41 (s, 3 H), 2.14 (s, 3 H), 2.58–2.78 (m, 2 H), 3.82–3.92
(m, 1 H), 3.95–4.10 (m, 2 H), 4.10–4.20 (m, 1 H), 4.25–4.33
(m, 1 H), 5.08–5.11 (m, 1 H). 13C NMR (126 MHz, CDCl3):
d = 20.8, 25.3, 26.5, 26.5, 27.3, 37.5, 66.1, 70.2, 72.8, 75.0,
79.3, 109.5, 109.7, 170.4, 174.6.
18: 3:2 mixture of diastereomers. 1H NMR (500 MHz,
CDCl3): d = 1.35, 1.36, 1.38, 1.44, 1.49, 1.51 (s, 12 H), 2.05,
2.06, 2.09, 2.10, 2.11 (s, 6 H), 2.60–2.90 (m, 2 H), 3.75–4.45
(m, 5 H), 5.00–5.50 (m, 2 H). 13C NMR (126 MHz, CDCl3):
d = 20.8, 20.9, 21.0, 25.1, 25.3, 25.4, 25.6, 26.0, 26.3, 26.3,
36.2, 36.4, 65.9, 67.1, 67.9, 69.3, 69.5, 70.2, 75.3, 75.4, 75.8,
76.5, 76.6, 76.9, 109.0, 109.2, 110.2, 169.9, 170.0, 170.2,
170.4, 174.4, 174.9.
14: 1H NMR (500 MHz, CDCl3): d = 2.05 (s, 3 H), 2.102 (s,
3 H), 2.104 (s, 3 H), 2.11 (s, 6 H), 2.63 (dd, J = 6.1, 16.8 Hz,
1 H), 2.69 (dd, J = 6.1, 16.8 Hz, 1 H), 4.03 (dd, J = 6.1, 11.9
Hz, 1 H), 4.27 (dd, J = 4.3, 11.9 Hz, 1 H), 5.30–5.45 (m, 4
Synlett 2007, No. 20, 3201–3205 © Thieme Stuttgart · New York

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