Ruthenium-catalysed selective transetherification of substituted vinyl ethers to form acetals and aldehydes

Article abstract of DOI:10.1002/ejic.200390212

The water-soluble ruthenium allenylidene complex [{RuCl(μCl)(C=C=CPh₂)(TPPMS)₂}₂] Na₄ catalyses the selective transformation of substituted linear and cyclic vinyl ethers with MeOH, under mild non acidic conditions, to give acetals, while aldehydes and ketones are obtained in a CHCl₃/H₂O mixture, which allows for easy recycling of the catalyst. NMR studies showed that the reaction follows a transetherification mechanism rather than simple acid-catalysed hydrolysis. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).

Full text of DOI:10.1002/ejic.200390212

FULL PAPER
Ruthenium-Catalysed Selective Transetherification of Substituted Vinyl Ethers
To Form Acetals and Aldehydes
[a]
[a]
[a]
[b]
Mustapha Saoud, Antonio Romerosa,* Sonia Ma n˜ as Carpio, Luca Gonsalvi, and
Maurizio Peruzzini*[
b]
Keywords: Ruthenium / Allenylidenes / Vinyl ethers / Homogeneous catalysis / Acetals
The water-soluble ruthenium allenylidene complex [{RuCl(µ-
mixture, which allows for easy recycling of the catalyst. NMR
Cl)(C=C=CPh )(TPPMS) ]Na catalyses the selective trans- studies showed that the reaction follows a transetherification
2
2
}
2
4
formation of substituted linear and cyclic vinyl ethers with
MeOH, under mild non acidic conditions, to give acetals,
while aldehydes and ketones are obtained in a CHCl /H O
3 2
mechanism rather than simple acid-catalysed hydrolysis.
( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2003)
Introduction
complex, we decided to investigate its behaviour under the
[
8Ϫ11]
conditions of RCM of acyclic dienes,
a reaction which
is well-known with several Grubbs-type ruthenium cata-
Unsaturated transition-metal carbene complexes, Mϭ
[
12,13]
[14]
[1]
lysts,
However, in spite of our expectations, the reaction of 1
in a biphasic CHCl /H O system with representative sub-
including the few that are soluble in water.
Cϭ(C) ϭC, such as vinylidenes (n ϭ 0) and allenylidenes
n
[
2]
(
n ϭ 1), are a ubiquitous class of organometallic com-
pounds whose use in catalysis has gained an increasing con-
3
2
sideration during the last decade.[3] In this regard, particu-
strates such as diethyl diallylmalonate and N,N-diallyltosyl-
amide failed to give any RCM reaction. Thus, when 1,4-
butanediol vinyl ether (2) was chosen as substrate, we ob-
served that, although not affording RCM products as re-
lar emphasis has been placed on ruthenium vinylidene com-
plexes, which have been shown to catalyze several important
processes targeting the elaboration of linear and cyclic or-
[
15]
[
3,4]
ported for other Ru-carbene species, complex 1 was still
endowed with catalytic activity, bringing about the selective
formation of ethanal and 1,4-butandiol, followed by their
intermolecular condensation to generate 2-methyl-[1,3]di-
oxepane (3) in almost quantitative yield. When the same
reaction was carried out in methanol, the isolated products
were 1,1-dimethoxyethane and 1,4-butanediol (Scheme 1).
Although this catalytic method is of little synthetic interest,
and the reaction under scrutiny can be performed without
the need for expensive transition-metal catalysts, this seren-
dipitous discovery nevertheless represents a completely new
reaction to the best of our knowledge, and on this basis we
decided to study its general applicability and tried to un-
ravel its mechanism.
ganic compounds.
More recently, ruthenium allenylidene
species have also started attracting interest as catalysts or
catalyst precursors and have been employed to achieve im-
portant metal-mediated reactions such as alkene ring clos-
[
5aϪ5e]
ing metathesis (RCM),
ring opening metathesis pol-
[
5f,5h]
ymerisation
and propargylation of aromatic com-
[
6]
pounds.
In a previous communication we have described the first
example of a water-soluble transition metal allenylidene
complex
of
formula
(1) [TPPMS
C H } }]. As a first exploratory assessment of its cata-
[{RuCl(µ-Cl)(CϭCϭCPh )-
2
(
TPPMS) } ]Na
ϭ
Ph P{2-OS(O) -
2 2
2
2
4
Ϫ
[7]
6
4
lytic activity, we have demonstrated that this ruthenium()
complex may be successfully used in the selective ring-open-
ing metathesis (ROM) of cyclic olefins with methylacrylate
as chain-transfer reagent. In order to further evaluate the
catalytic activity of this water-soluble unsaturated carbene
[
a]
´
Area de Quimica Inorganica, Universidad de Almer ´ı a,
0
4071, Almer ´ı a, Spain
Fax: (internat.) ϩ34-950/015-008
E-mail: romerosa@ual.es
[
b]
Istituto di Chimica dei Composti Organometallici, ICCOM-
CNR,
Via Jacopo Nardi 39, 50132 Firenze, Italy
Fax: (internat.) ϩ39-055/247-8366
E-mail: peruz@fi.cnr.it
Scheme 1
1614  2003 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim 1434Ϫ1948/03/0408Ϫ1614 $ 20.00ϩ.50/0 Eur. J. Inorg. Chem. 2003, 1614Ϫ1619

Ruthenium-Catalysed Selective Transetherification of Substituted Vinyl Ethers
FULL PAPER
Results and Discussion
Table 2. Catalytic reactions of linear and cyclic vinyl ethers in the
presence of 1 in CD
3
OD[
a]
In order to explore the scope of the reaction, we applied
our catalytic system to a series of linear and cyclic vinyl
ethers bearing different functional groups. The nature of
the final products depends strictly on whether the reactions
are run under monophasic (MeOH) or biphasic (CHCl3/
H O) conditions. All the tests were run under very mild
2
conditions (47 °C). The results are summarised in Table 1
and 2 for biphasic and monophasic conditions, respectively.
Our protocol is highly specific for vinyl ethers, as diallyl,
diethyl, dibenzyl and allylpropargyl ethers were recovered
intact after the catalytic tests. This indicates a high toler-
ance of the method for a wide variety of organic substrates
and suggests a potential application for the selective depro-
tection of masked aldehydes protected as vinyl ethers, such
as acid sensitive β-hydroxy aldehydes. However, only trivial
products were obtained from the ethers of choice as these
were deliberately chosen for screening purposes only.
[a]
Reaction conditions: substrate (0.1 mmol), 1 (0.005 mmol),
CD OD (1.0 mL), 47 °C, 17 h, in NMR tube (5 mm) under Ar
3
Table 1. Catalytic reactions of linear and cyclic vinyl ethers in the
presence of 1 in CDCl /D O
3 2
[a]
uteration at the 2-position follows from H/D exchange via
a keto-enol equilibrium (see Scheme 4 in the Exp. Sect.).
For linear vinyl ethers the formation of CD -diacetals was
3
observed, resulting from the condensation of acetaldehyde
and CD OD by cleavage of the vinyl carbon-oxygen bond.
3
For example, 2-bromovinyl ethyl ether was converted into
2-bromo-2-deutero-1,1-bis(trideuteromethoxy)ethane
(Table 2, entry 8). For cyclic vinyl ethers such as dihydropy-
ran, ring opening and acetalization occur to give the pro-
tected 5-trideuteroxy-2-deuteropentan-1-al (Table 2, entry
10). 1-Methoxy1,3-cyclohexadiene was converted into the
deuterated OCD analogue (kinetic product) instead of the
3
corresponding diacetal (Table 2, entry 9) which forms only
after a week at 47 °C.
We chose 1,4-butanediol vinyl ether (2) to test the effect
of catalyst concentration on the rate and selectivity of the
[
a]
Reaction conditions: substrate (0.1 mmol), 1 (0.005 mmol),
CDCl (0.5 mL), D O (0.5 mL), 47 °C, 2.5 h, in NMR tube (5 mm)
under Ar. Bromoacetaldehyde is not stable under the reaction
conditions and cyclotrimerizes to 2,4,6-tris(bromodeuteromethyl)-
3
2
[
b]
reaction. In CDCl /D O, the reaction reached completion
3
2
,3,5-trioxane (see Exp. Sect.). [ The aldehyde 5-hydroxypentanal in 2.5 hours with 5 mol % of catalyst 1, 8 h with 1 mol %
c]
1
intramolecularly condenses to 3-deuterotetrahydro-2H-pyran-2-de-
uterol, equilibrium yield 84% (see Exp. Sect.).
and 20 h with 0.2 mol %, in all cases with selectivity higher
than 99%. In CD OD, the reaction is slower (17 h) and nor-
3
mally 5 mol % of 1 are required to complete the reaction
The reactions were carried out on an NMR-tube scale at in a comparable time scale. The nature of the ruthenium
first and then repeated in bulk to check for reproducibility precursor was also found to be crucial for the reaction. A
and to isolate the products. For all reactions the two meth- series of precursors was tested for the reaction of 2 under
ods gave similar results, showing that NMR-scale tests can standard conditions; the results are summarised in Table 3.
be representative of the actual catalytic test under the same Remarkably, while the classic Grubbs catalyst does not
conditions. Under NMR tube reaction conditions, at 47 °C work under these reaction conditions, the water-soluble
with a 1:1 CDCl /D O mixture, all vinyl substrates were phenylvinylidene complex [RuCl {CϭC(H)Ph}(TPPMS) ]-
3
2
2
2
[
7]
smoothly converted within three hours, reaching complete Na (4) shows a similar reactivity to 1 in promoting the
2
selectivity for the products described in Table 1, as deter- acetalization of 2. These results are significant and indicate
mined by NMR spectroscopy and GC-MS techniques. The that ruthenium, TPPMS and unsaturated carbenes are
deep-red coloured catalytically active species remains con- necessary ingredients in this reaction either as molecular
fined to the water phase and can be recycled up to four complexes or to form the catalytic species in situ (Table 3,
times without significant loss of activity (see Exp. Sect.).
entries 18 and 19). However, catalytic tests with isolated
An interesting reaction is the selective deuteration of 1- samples of 4 were not systematically evaluated due to the
methoxy-1,3-cyclohexadiene to yield 2,2-dideuterocyclohex- lower stability and difficulty of isolation of 4 compared to
3
-en-1-one (Table 1, entry 4) where the selective double de- 1.[7]
Eur. J. Inorg. Chem. 2003, 1614Ϫ1619
1615

M. Saoud, A. Romerosa, S. M. Carpio, L. Gonsalvi, M. Peruzzini
Table 3. Blank reactions and effect of Ru precursor on the conversion of 2 to 1,4-D-butanediol and 1,1-D-dimethoxy-2-D-ethane[a]
FULL PAPER
Entry
Precursor
Yield (%)
Time (h)
11
12
13
14
15
16
17
18
19
None
TPPMS
[RuCl
[Cp*Ru(PEt
[RuCl
[RuCl
[RuCl
[RuCl
[RuCl
Ϫ
Ϫ
Ϫ
Ϫ
Ϫ
80
30
93
95
70
70
20
20
20
1 month
18
16
17
2
(CHPh)(PCy
Cl]
3
)
2
]
3
)
2
2
2
2
2
2
(PPh
(TPPMS)
3
)
3
]
2
]
2
(PPh
(PPh
(PPh
3
3
3
)
3
)
3
)
3
] ϩ 4 TPPMS
] ϩ 4 TPPMS ϩ HCϵCPh
] ϩ 4 TPPMS ϩ HCϵCC(OH)Ph
2
[
a]
Reaction conditions: substrate (0.1 mmol), precursor (0.005 mmol), CD OD (1.0 mL), 47 °C, 17 h, in NMR tube (5 mm) under Ar
3
We obtained evidence for a transetherification mecha- thenium species (singlet at δ ϭ 21.4 ppm), which remains
nism by monitoring the reaction of 2 with 1 in CD OD by catalytically active over more than four runs.
3
1
13
1
H and C{ H} NMR spectroscopy at 47 °C. The decrease
in the intensity of the signal at δ ϭ 6.49 ppm (dd, JH,H
ϭ
Conclusion
In summary, our study provides an insight into the reac-
tivity of vinyl ethers in the presence of a Ru-allenylidene
complex and an alternative method for the production of
acetals, aldehydes and ketones from a wide choice of vinyl
[
19]
ether precursors.
Although the present method is cer-
tainly not convenient for routine applications, it is import-
ant to stress that this protocol affords catalytic solvolysis of
vinyl ethers under mild conditions at neutral pH in aqueous
phase or anhydrous organic phase, with high tolerance for a
variety of functional groups. As a consequence, the present
ruthenium catalyst might deserve application in particular
Scheme 2. NMR mechanistic experiments: (a) 2, 0.1 mmol; 1, cases where the vinyl ether functionality is coupled with
3
0
.005 mmol. CD
3
OD 1.0 cm ; 47 °C; 24 h, in NMR tube (5 mm)
OD 1.0 mL; 47
acid-sensitive groups. We are currently investigating more
interesting applications of the catalytic protocol, such as the
under Ar; (b) 2, 0.1 mmol; HOTs, 0.01 mmol. CD
C; 24 h, in NMR tube (5 mm) under Ar
3
°
[
20]
synthesis of polyacetals
and podands. Preliminary
experiments showed that our system is active in the selective
catalytic synthesis of a variety of linear polyethers by acetal-
ization of vinyl ethyl ether with various glycols.
a
1
4.3, 7.0 Hz) due to the vinyl proton H (Scheme 2a) was
accompanied by an increase in the intensity of a new signal
at δ ϭ 6.51 ppm (dd, J ϭ 14.2, 6.8 Hz) that we attribute
to H , which in turn decreases in intensity with the appear-
ance of the signal due to H at δ ϭ 4.56 ppm (dt, J
.2, JH,D ϭ 1.8 Hz) belonging to the final product. A paral-
lel experiment, carried out replacing 1 with HOTs, ruled out
the possibility of acid-catalysed hydrolysis of the substrate
Under these conditions, 2 is immedi-
ately converted into a new species that does not contain a
H,H
b
c
ϭ
Experimental Section
H,H
5
General Remarks: Complex 1 was prepared as described pre-
viously.[ H and C{ H} NMR spectra were recorded on Varian
7] 1
13
1
[
16Ϫ18]
VXR300, or Bruker AVANCE DRX300 spectrometers operating at
(Scheme 2b).
1
13
ca. 300 MHz ( H) and ca. 75.4 MHz ( C). Peak positions are rela-
tive to tetramethylsilane and were calibrated against the residual
vinyl group, is stable and is plausibly the product of ad-
dition of CD OD to the vinyl double bond as evidenced by
the diagnostic H signal at δ ϭ 4.66 ppm (dt, JH,H ϭ 5.4,
1
13
solvent resonance ( H) or the deuterated solvent multiplet ( C).
P{ H} NMR spectra were recorded on the same instruments op-
erating at ca. 121 MHz. Chemical shifts were measured relative to
3
31
1
d
JHD ϭ 1.6 Hz). Although a detailed mechanism cannot be external 85% H PO with downfield values taken as positive. A
3
4
proposed on the basis of the NMR study alone, these latter Shimadzu GC-14A/GCMS-QP2000 instrument was employed for
experiments suggest that the reaction occurs as a two-step GC-MS investigations.
transformation of the vinyl substrate by exchange of the
ether substituent, followed by addition of alcohol to the
Bulk-Scale Experiments: In a typical macro scale experiment,
3
mmol of substrate were added under argon to 2 mL of MeOH
CϭC double bond with regioselective deuteration of the β-
together with 0.03 mmol of 1. After 2 h whilst stirring at 47 °C the
3
1
1
carbon. P{ H} NMR monitoring of the biphasic reaction solvent was removed giving the 1,1-dimethoxy-substituted product.
shows that 1 quantitatively transforms into an unknown ru- When a biphasic system was used, 3 mmol of vinyl ether and
1616
Eur. J. Inorg. Chem. 2003, 1614Ϫ1619

Ruthenium-Catalysed Selective Transetherification of Substituted Vinyl Ethers
FULL PAPER
0
H
.03 mmol of 1 were dissolved into 1 mL of CHCl
O under argon. The mixture was kept at 47 °C for 1 h under nent) and the cyclotrimer. H NMR (300.13 MHz, CDCl
vigorous stirring, then the organic phase was separated and dried temp.): bromoacetaldehyde: δ ϭ 9.55 (d, JH,H ϭ 2.5 Hz, CHO),
over MgSO . The aldehyde or ketone was obtained in nearly quan-
3
and 1 mL of
mixture reveals the presence of both the aldehyde (minor compo-
1
2
3
, room
4
3.86 (dt, JH,H ϭ 6.8, JH,D ϭ 2.5 Hz, CHDBr) ppm; 2,4,6-tris(bromo-
deuteromethyl)-1,3,5-trioxane: δ ϭ 4.68 (d, JH,H ϭ 5.5 Hz,
CHOO), 3.61 (dt, JH,H ϭ 5.5, JH,D ϭ 1.9 Hz, CHDBr) ppm.
titative yield by evaporation at reduced pressure of the solvent.
Typical Experimental Procedure for NMR-Tube Tests. (a) Mono-
phasic Conditions: Compound 1 (11 mg, 5 ϫ 10 mmol) was intro-
duced into a 5 mm NMR tube, which was repeatedly evacuated
and filled with argon. The substrate (20 equiv., typically 15Ϫ18 µL)
was then added together with 0.5 mL of CD
orange-red homogeneous solution. The tube was kept in an oil bath
at 47 °C for typically 15Ϫ17 hours after which H and C NMR
13
1
C{ H} NMR (75.47 MHz, CDCl
hyde: δ ϭ 191.9 (s, CHO), 52.2 (t, JC,D ϭ 18.5 Hz, CHDBr) ppm.
,4,6-tris(bromodeuteromethyl)-1,3,5-trioxane: 101.36 (s,
3
, room temp.): bromoacetalde-
Ϫ3
2
δ ϭ
CHOO), 51.7 (t, JC,D ϭ 18.5 Hz, CHDBr) ppm. GC/MS: not regis-
tered.
3
OD, to obtain an
1
13
spectra were collected.
(b) Biphasic Conditions: As above, except for solvent (a mixture of
CDCl , 0.5 mL and D O, 0.5 mL was used) and reaction time (typi-
3
2
cally 3 h). The tube was shaken thoroughly after mixing of the re-
agents and before taking the NMR spectra.
Experimental Procedure for Catalyst Recycling Tests: An NMR
tube was charged with 1 (12.5 mg, 5.7 ϫ 10 mmol), 2 (18 µL,
Scheme 3
Ϫ3
3 2
0.114 mmol), 0.5 mL of CDCl and 0.5 mL of D O. The tube con-
taining two separate phases was kept at 47 °C for 3 h, during which
time it was shaken approximately every 20 min. After separation of
the organic phase, the aqueous phase, which contained the catalyst,
was proved to be active in the catalytic reaction during three ad-
2
,2-Dideuterocyclohex-3-enone: (Table 1, entry 4). The product
probably forms by selective incorporation of deuterium in position
following H/D exchange. The latter is likely to be promoted by
the keto-enol equilibrium depicted in Scheme 4.
2
ditional runs carried out by adding 18 µL of 2 to 0.5 mL of CDCl
a 100% conversion of 2 was achieved after 2.3 h in the first cata-
3
1
H NMR (300.13 MHz, CDCl
3
, room temp.): δ ϭ 2.34 [m, 4 H,
(
CH2(5)CH2(6)], 6.03 [dt, JH,H ϭ 10.3, JH,H ϭ 1.9 Hz, 1 H, CH(4)],
lytic run, after 2.5 h in the second catalytic test and after 2.75 h in
the third run). Only in the fourth catalytic run was a significant
decrease of the catalytic activity observed — the reaction time to
transform all of the substrate rose to about 4 h.
1
3
1
6
(
1
.97 [dm, JH,H ϭ 10.3 Hz, 1 H, CH(3)] ppm. C{ H} NMR
75.47 MHz, CDCl , room temp.): δ ϭ 205.2 [C(1)],130.9 [s, C(4)],
28.2 [s, C(3)], 41.9 [s, C(6)], 38.0 [quin., JC,D ϭ 19.7 Hz, C(2)], 22.6
O], 82
3
[s, C(5)] ppm. GC/MS: m/z (%) ϭ 98 (18) [C
6
H
6
D
2
(
6 6 2 5 6 2
5)[C H D ], 70 (100%) [C H D ].
NMR and GC-MS Product Characterisation
-Deuteromethyl-[1,3]dioxepane: (Table 1, entry 1). 1H NMR
300.13 MHz, CDCl , room temp.): δ ϭ 1.32 (dt, JH,H ϭ 5.16,
H,D ϭ 1.8 Hz, 2 H, CH D), 1.70 (m, 4 H, OCH CH ), 3.67 (m, 2
2-Deutero-5-deuteroxypentanal: (Table 1, entry 5). The aldehyde
that forms selectively from the cyclic vinyl ether 3,4-dihydro-2H-
pyran, undergoes acetalization under the present reaction con-
ditions and intramolecularly condenses to yield 3-deuterotetrahy-
dro-2H-pyran-2-deuterol. The NMR analysis indicates the forma-
tion of an equilibrium mixture with about 84% of the cyclic com-
2
(
J
3
2
2
2
H, OCHH), 3.93 (m, 2 H, OCHH), 4.95 (t, JH,H ϭ 5.16 Hz,
OCHO) ppm. 1 C{ H} NMR (75.47 MHz, CDCl
δ ϭ 28.9 (s, OCH CH ), 66.4 (2 OCH ), 100.4 (s, OCHO), 31.7 (t,
C,D ϭ 18.5 Hz, CH D) ppm. GC/MS: m/z (%) ϭ 117 (5)
D], 101 (43) [C ], 71 (87) [C O], 55 (53) [C ],
3 (100) [C O].
3
1
3
, room temp.):
2
2
2
pound (Scheme 5).
J
2
1
3
H NMR (300.13 MHz, CDCl , room temp.): 2-deutero-5-deut-
[
C
6
H
11
O
2
5
H
9
O
2
4
H
7
4 7
H
eroxypentanal: δ ϭ 9.79 (s, 1 H, CHO), 3.46 (m, 2 H, CH
.5Ϫ2.1 [m, 5 H, CH(D)CH CH
pyran-2-deuterol: δ ϭ 4.27 [m, 1 H, OCH(OD)], 3.53 (t, J
2
OD),
4
2 3
H
1
2
2
] ppm; 3-deuterotetrahydro-2H-
Deuteroacetaldehyde: (Table 1, entries 1, 2). 1H NMR
300.13 MHz, CDCl
H, CHO), 2.19 (dt, JH,H ϭ 2.80, JH,D ϭ 2.25 Hz, 2 H, CH
H,H
3 1
ϭ
1
(
3
, room temp.): δ ϭ 9.79 (br. t, JH,H ϭ 2.80 Hz, 7.4 Hz, 2 H, CH O), 1.5Ϫ2.0 (m, CH CH ϩ CHD) ppm. C{ H}
2 2 2
1
2
D)
, room temp.): δ ϭ 200.89 pentanal: δ ϭ 200.1 (s, CHO), 62.2 (s, CH OD), 30.4 (t, JC,D
ϭ
3
NMR (75.47 MHz, CDCl , room temp.): 2-deutero-5-deuteroxy-
13
1
ppm. C{ H} NMR (75.47 MHz, CDCl
s, CHO), 21.49 (t, JC,D ϭ 19.5 Hz, CH
registered.
3
2
(
2
D) ppm. GC/MS: not 19.5 Hz, CHD), 27.2 (s, CH CH OD), 19.6 (s, CHDCH ) ppm;
2 2 2
3-deuterotetrahydro-2H-pyran-2-deuterol: δ ϭ 94.5 [s, OCH(OD)],
6
2
8
2.9 (s, CH
0.1 (s, CH
5 (10) [C
2
O), 29.7 (t, JC,D ϭ 36.3 Hz, CHD), 25.2 (s, CH
CHD) ppm. GC/MS: m/z (%) ϭ 103 (23) [C
OD], 58 (100) [C OD], 42 (60) [C D].
2
CH
2
O),
],
Bromodeutero Acetaldehyde: (Table 1, entry 3). Bromoacetaldehyde,
which selectively forms from the reaction of 1 with 1-bromo-2-
ethoxyethene, is not stable under the reaction conditions and cyclo-
trimerizes spontaneously to 2,4,6-tris(bromodeuteromethyl)-1,3,5-
2
5
H
7
O
2
D
2
5
H
7
3
H
4
3 4
H
1,4-Butandeuterol: (Table 2, entry 6). 1H NMR (300.13 MHz,
3 2
trioxane (see Scheme 3 below). The NMR analysis of the reaction CDCl , room temp.): δ ϭ 3.67 (m, 4 H, 2 ϫ OCH ), 1.64 (m, 4 H,
Scheme 4
Eur. J. Inorg. Chem. 2003, 1614Ϫ1619
1617

M. Saoud, A. Romerosa, S. M. Carpio, L. Gonsalvi, M. Peruzzini
FULL PAPER
Scheme 5
1
2
ϫ OCH
temp.): δ ϭ 30.2 (s, 2 ϫ OCH
MS: m/z (%) ϭ 92 (2) [C
2
CH
2
) ppm. 13C{ H} NMR (75.47 MHz, CDCl
3
, room tivity. AR thanks MCYT (Spain) for project PPQ2000-1301 and
2
CH
2
), 62.6 (s, 2 ϫ OCH
], 86 (5) [C
O].
2
) ppm. GC/
the Junta de Andalucia for project A29/00. Dr. G. Reginato (IC-
4
H
8
O
2
D
2
4 6 2
H O ], 71 (18) COM-CNR) is gratefully acknowledged for helpful discussions.
[C
4
H
7
O], 57 (11) [C
3
H
5
O], 42 (100) [C
2
H
2
2
-Deutero-1,1-bis(trideuteromethoxy)ethane: (Table 2, entries 6,7).
1
H NMR (300.13 MHz, CDCl
.2 Hz, 1 H, CH(OCD ], 1.26 (dt, JH,H ϭ 5.2, JH,D ϭ 1.8 Hz, 2
D) ppm. 13C{ H} NMR (75.47 MHz, CDCl
, room temp.):
δ ϭ 101.2 [s, CH(OCD ], 47.5 (sept, JC,D ϭ 21.3 Hz, OCD ),
7.2 (t, JC,D ϭ 18.7 Hz, CH D) ppm. GC/MS: m/z (%) ϭ 96 (5)
], 81 (53) [C HO ], 63 (100) [C HO ], 44 (27)
3
, room temp.): δ ϭ 4.56 [t, JH,H ϭ
[
1] [1a]
M. I. Bruce, Chem. Rev. 1991, 91, 197Ϫ257. [1b] M. C.
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3 2
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1
H, CH
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3
9
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2
3
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1
[3] [3a]
1
2
3b]
[C
4
H
3
O
2
D
7
3
2
D
6
2
2 3
D
[3c]
H. Werner, Chem. Commun.
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[4] [4a]
[CO
2
].
3d]
1
-Bromo-1-deutero-2,2-bis(trideuteromethoxy)ethane: (Table 2, en-
1
try 8). H NMR (300.13 MHz, CDCl
H,H ϭ 5.2 Hz, 1 H, CH(Ocd ], 3.40 (m, 1 H, CHDBr) ppm.
C{ H} NMR (75.47 MHz, CDCl , room temp.): δ ϭ 103.1 [s,
CH(Ocd ], 29.8 (t, JC,D ϭ 23 Hz, CHDBr) ppm. GC/MS: m/z
%) ϭ 176 (6) [C Br], 142 (30) [C OD Br], 108 (5)
DBr], 81 (100) [HBr].
-Trideuteromethoxy-1,3-cyclohexadiene: (Table 2, entry 9). 1H
3
, room temp.): δ ϭ 4.55 [d,
C. Bruneau, P. H. Dixneuf, Acc. Chem. Res. 1999, 32,
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3
11Ϫ323. [ B. M. Trost, Acc. Chem. Res. 2002, 35, 695Ϫ705
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J
3 2
)
13
1
3
[5] [5a]
A. Fürstner, M. Picquet, C. Bruneau, P. H. Dixneuf, Chem.
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3 2
)
5b]
(
4
H
2
O
2
D
7
3
H
2
4
[C
2
H
2
[5c]
M. Picquet, D. Touchard, C. Bruneau, P. H. Dixneuf, New
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J. Chem. 1999, 23, 141Ϫ143.
D. S e´ meril, H. Oliver-
1
Borbigon, C. Bruneau, P. H. Dixneuf, Chem. Commun. 2002,
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3
, room temp.): δ ϭ 5.86 [m, 1 H, CH(3)],
46Ϫ147. [ D. S e´ meril, C. Bruneau, P. H. Dixneuf, Adv.
5e]
1
5
.40 [br. d, JH4,H3 ϭ 7.9 Hz, 1 H, CH(4)], 4.97 [d, JH,H ϭ 5.1 Hz, 1
[5f]
Synth. Catal. 2002, 344, 585Ϫ595.
S. Jung, C. D. Brandt,
H, CH(2)], 2.21 [m, 4 H, CH2(5)CH2(6)] ppm. 13C{ H} NMR
75.47 MHz, CDCl , room temp.): δ ϭ 127.8 (s, C3), 120.1 (s, C1),
13.4 (s, C4), 76.7 (s, C2), 54.8 (sept, JC,D ϭ 21.3 Hz, OCD ), 25.1
s, C5), 22.2 (s, C6) ppm. GC/MS: m/z (%) ϭ 114 (40) [C ],
1
[5g]
H. Werner, New J. Chem. 2001, 25, 1101Ϫ1103.
R.
(
1
(
3
´
Castarlenas, D. Semeril, A. F. Noels, A. Demonceau, P. H.
[5h]
3
Dixneuf, J. Organomet. Chem. 2002, in press.
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82Ϫ183, 577Ϫ583.
I. A. Abdalla-
8 7 2 7
H O D
1
6 8 6 8
96 (100) [C H O], 80 (62) [C H ].
[
[
6]
7]
Y. Nishibayashi, M. Yoshikawa, Y. Inada, M. Hidai, S. Ue-
mura, J. Am. Chem. Soc. 2002, 124, 11846Ϫ11847.
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19, 4005Ϫ4007.
[
[
8]
9]
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L. Jafarpour, S. P. Nolan, J. Organomet. Chem. 2001,
6
17/618, 17Ϫ27.
[10]
4
-Deutero-5,5-bis(trideuteromethoxy)pentan-1-deuterol:
(Table 2,
, room temp.): δ ϭ 4.50
OD),
C{ H} NMR
, room temp.): δ ϭ 99.8 [s, CH(OCD ], 61.7
OD), 48.1 (sept, JC,D ϭ 21.8 Hz, OCD ), 29.8 (t, JC,D
9.7 Hz, CHD), 18.9 and 25.1 (all s, CH CH ) ppm. GC/MS: m/z
%) ϭ [C ] not observed, 120 (30) [C ], 86 (70)
OD], 57 (100) [C D], 42 (60) [C D].
A. Fürstner, M. Liebl, C. W. Lehmann, M. Picquet, R. Kunz,
C. Bruneau, D. Touchard, P. H. Dixneuf, Chem. Eur. J. 2000,
1
entry 10). H NMR (300.13 MHz, CDCl
3
6, 1847Ϫ1857.
[
1
(
(
br. s, 1 H, CH(OCD
.53Ϫ1.80 (m, H, CHDCH
75.47 MHz, CDCl
s, CH
3 2 2
) ], 3.68 (br. t, JH,H ϭ 6.2 Hz, CH
[
[
11]
12]
13
1
A. Fürstner, Angew. Chem. Int. Ed. 2000, 39, 3013Ϫ3043.
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5
2 2
CH ) ppm.
3
3 2
)
1
15, 9856Ϫ9857.
2
3
ϭ
[13]
[14]
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997, 119, 3887Ϫ3897.
1
(
2
2
1
7
H
8
O
3
D
8
6 6 2 5
H O D
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[C
5
H
8
4
H
7
3 4
H
[
[
[
[
15]
16]
17]
18]
9
623Ϫ9626.
T. Okuyama, T. Fueno, H. Nakatsuji, J. Furukawa, J. Am.
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Acknowledgments
This work was supported by INTAS (00-00018) and NATO (PST-
CLG-978521). Thanks are also due to EU through COST D17
Chemistry Action (WGD17/003) for promoting this scientific ac-
G. E. Lienhard, T.-C. Wang, J. Am. Chem. Soc. 1969, 91,
1146Ϫ1153.
A. J. Kresge, H. J. Chen, J. Am. Chem. Soc. 1972, 94,
2818Ϫ2822.
1618
Eur. J. Inorg. Chem. 2003, 1614Ϫ1619

Ruthenium-Catalysed Selective Transetherification of Substituted Vinyl Ethers
FULL PAPER
[
19]
II
Substituted vinyl ethers can be obtained via Hg -catalysed al-
acetate) films. Alkyl-, cycloalkyl- and aryl-substituted polyacet-
als can be obtained from metal-catalysed reaction of vinyl acet-
ate with alkyl orthoesters in the presence of a Lewis acid, see
F Bauer, C. Subramaniam, US Patent 6 355 844, 2002.
Received November 5, 2002
cohol vinylation, see: W. H. Watanabe, L. E. Conlon, J. Am.
Chem. Soc. 1957, 79, 2828Ϫ2833; or by Ir-catalysed activation
of vinyl acetate in alcohols, see: Y. Okimoto, S. Sakaguchi, Y.
Ishii, J. Am. Chem. Soc. 2002, 124, 1590Ϫ1591.
[
20]
Polyacetals are used as intermediates for the synthesis of heter-
ocycles, as hardeners for poly(vinyl alcohol)s and poly(vinyl
[I02615]
Eur. J. Inorg. Chem. 2003, 1614Ϫ1619
1619