Ruthenium-catalyzed o-allylation of phenols from allylic chlorides via cationic [Cp*(η3-allyl)(MeCN)RuX][PF6] complexes

Article abstract of DOI:10.1002/adsc.200404023

The [Cp*(MeCN)₃Ru(II)][PF₆] complex is an efficient catalyst precursor for the O-allylation of phenols with allylic chlorides in the presence of K₂CO₃ under mild conditions. This ruthenium precursor affords branched allyl aryl ethers according to a regioselective reaction, which contrasts with the uncatalyzed nucleophilic substitution from the same substrates. Stable (η³-allyl)Ru(IV) cationic complexes resulting from the reaction of [Cp*(MeCN) ₃Ru][PF₆] with allylic halides were identified as intermediate catalytic species. An X-ray structure determination of the complex [Cp*(MeCHCHCH₂)(MeCN)RuBr] [PF₆] disclosed an (endo-trans-MeCHCHCH₂) allylic ligand. The structural information obtained from the study of Cp*(allyl)Ru(IV) complexes indicated that electronic effects at the coordinated allylic ligand likely account for the better regioselectivity obtained from cinnamyl chloride as compared to aliphatic allylic chlorides.

Full text of DOI:10.1002/adsc.200404023

FULL PAPERS
Ruthenium-Catalyzed O-Allylation of Phenols from Allylic
Chlorides via Cationic [Cp*(h3-allyl)(MeCN)RuX][PF6]
Complexes
Mbaye D. Mbaye,a Bernard Demerseman,a* Jean-Luc Renaud,a LoÔc Toupet,b
Christian Bruneaub,*
a
¬
¬
Institut de Chimie, UMR 6509: CNRS Universite de Rennes 1, Organometalliques et Catalyse, Campus de
Beaulieu-35042 Rennes Cedex, France
Fax: [þ33]-2-23-23-69-39, e-mail: bernard.demerseman@univ-rennes1.fr, christian.bruneau@univ-rennes1.fr
b
¬
¡
¬
¬
Universite de Rennes 1, Groupe Matiere Condensee et Materiaux, UMR CNRS 6626, Campus de
Beaulieu-35042 Rennes Cedex, France
Fax: [þ33]-2-23-23-64-97, e-mail: loic.toupet@univ-rennes1.fr
Received: January 22, 2004; Accepted: April 5, 2004
Dedicated to Dr. Joe P. Richmond on the occasion of his 60th birthday in appreciation of his expertise and
tremendous activity in the field of scientific publishing.
Abstract: The [Cp*(MeCN)3Ru(II)][PF6] complex is of the complex [Cp*(MeCHCHCH2)(MeCN)RuBr]
an efficient catalyst precursor for the O-allylation of [PF6] disclosed an (endo-trans-MeCHCHCH2) allylic
phenols with allylic chlorides in the presence of ligand. The structural information obtained from the
K2CO3 under mild conditions. This ruthenium precur- study of Cp*(allyl)Ru(IV) complexes indicated that
sor affords branched allyl aryl ethers according to a electronic effects at the coordinated allylic ligand
regioselective reaction, which contrasts with the unca- likely account for the better regioselectivity obtained
talyzed nucleophilic substitution from the same sub- from cinnamyl chloride as compared to aliphatic allyl-
strates. Stable (h3-allyl)Ru(IV) cationic complexes re- ic chlorides.
sulting from the reaction of [Cp*(MeCN)3Ru][PF6]
with allylic halides were identified as intermediate Keywords: allylation; allylic ligands; homogeneous
catalytic species. An X-ray structure determination catalysis; regioselectivity; ruthenium
Introduction
Allyl aryl ethers are valuable intermediates in organic
chemistry. Through a regioselective addition to unsym-
The oxidative addition of allylic halides to neutral metrical allylic ligands from allylic carbonates, enantio-
Cp*Ru(II) centers generating Cp*(h3-allyl)XRu(IV) selective syntheses of branched allyl aryl ethers have
complexes undoubtedly provides a crucial key for the been achieved by using chiral iridium or rhodium cata-
understanding of ruthenium-catalyzed allylic substitu- lysts.[10,11] On the other hand, palladium catalysts most
4]
tion reactions.[1 Thus, the neutral complex Cp*(h3- often favored the formation of linear allyl aryl
PhCHCHCH2)RuCl2 was isolated and structurally char- ethers.[12 14] An alternative copper-catalyzed etherifica-
acterized when the complex Cp*(cod)RuCl was in- tion of allylic alcohols with aryltrifluoroborate salts has
volved as a catalyst precursor.[5] Of primordial interest, been reported recently.[15] By contrast, the involvement
nucleophilic additions at unsymmetrical allylic ligands of aryloxide anions as nucleophiles in ruthenium-cata-
were shown to favor the formation of branched organic lyzed allylation is rare.[7]
compounds, and a remarkably high regioselectivity was
In our ongoing work on ruthenium allylic species, we
reached using [Cp*(MeCN)3Ru][PF6] as a cationic cata- report herein that the readily available [Cp*(MeCN)3
lyst precursor.[6,7] We have recently reported that new di- Ru][PF6] complex reacts with allylic halides to afford
cationic Cp*(h3-allyl)Ru(IV) complexes containing a the new [Cp*(h3-allyl)(MeCN)RuX][PF6] complexes,
bipyridine ligand are also efficient catalysts for the allyl- and behaves as an efficient catalyst precursor for the
ic substitution reaction.[8] By contrast, a monocationic ruthenium-catalyzed synthesis of allyl aryl ethers from
Cp*(h3-allyl)Ru(IV) complex containing nitrogen do- allylic chlorides and phenols. Electrophilic Cp*(h3-al-
nor ligands has revealed a sluggish catalytic activity.[9]
lyl)ClRu(IV) intermediates are likely the key for the se-
Adv. Synth. Catal. 2004, 346, 835 841
DOI: 10.1002/adsc.200404023
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Mbaye D. Mbaye et al.
FULL PAPERS
1
lective formation of branched ethers when the allylic li- two isomers, as determined by H NMR spectroscopy,
gand is unsymmetrical.
was unaffected after attempts at fractional crystalliza-
tion but was affected by the nature of the solvent. These
observations suggest a dynamic equilibrium between
the two species. Of interest, the 1H NMR spectra record-
ed from a CD3CN solution showed only uncoordinated
CH3CN, thus revealing that a fast substitution of the ace-
tonitrile ligand by CD3CN rapidly occurred in solution.
Such a behavior might account for a fast equilibrium be-
Results and Discussion
Synthesis of Complexes 2a f
A slight change in color was immediately observed when tween the two stereoisomers of 2c f. For both stereo-
an allylic halide was added at room temperature to a sol- isomers, the 1H NMR resonance of the RCH allylic pro-
3
ution of [Cp*(MeCN)3Ru][PF6] (1) in acetonitrile under ton disclosed, when available, a high J coupling con-
argon. Indicating also that a fast reaction had occurred, stant values (close to 11 Hz) indicating an anti configu-
the solution was now stable in air and the addition of di- ration. The synthesis of the bromo derivative 2d afford-
ethyl ether subsequently allowed the isolation of orange ed crystals of high quality. An X-ray structure
to red crystals of 2a f in 68 92% yield (Scheme 1). determination revealed 2d to form a monohydrate ad-
Complex 2a was thus easily prepared from allyl chloride, duct and showed the ruthenium atom to be coordinated
2b from 3-chloro-2-methylpropene, 2c from crotyl chlor- to a p-bonded C5Me5 ring, an h3-CH2CHCHMe allylic
ide or alternatively from 3-chloro-1-butene, 2d from cro- fragment displaying an endo orientation, and to an ace-
tyl bromide, 2e from a mixture of 1-chloro-2-hexene and tonitrile and a bromide ligand. An ORTEP view of 2d is
3-chloro-1-hexene (4:1), and 2f from cinnamyl chloride. shown in Figure 1 and selected bond distances and an-
The new complexes are weakly soluble in halogenated gles are reported in the caption.
hydrocarbons (2c f) such as CDCl3 or CD2Cl2 but are
It is worth to mention that an endo orientation of the
very soluble in acetonitrile, and were found to be stable allylic ligand in 2c f and an anti position of the RCH
in air at least in the solid state. Complexes 2a f were proton avoid steric hindrance between the R group
1
characterized from a combination of H, 13C{1H}, and and the C5Me5 ring. The observation of close
13C DEPT NMR spectroscopy, elemental analysis, and Br Ru CH2 and N Ru CHMe angles [81.7(2) and
an X-ray structure determination of 2d. The H NMR 82.7(2)8, respectively] provides evidence for a lack of
À
À
À
À
1
spectra of 2a f were consistent with the presence of steric constraints in 2d, that agrees with the presence
an h3-coordinated allylic fragment and showed 2a and of the two stereoisomers in solution, both as enantio-
2b (which both involve a symmetrical allylic ligand) as
1
single species in solution. By contrast, the H NMR
spectra of 2c f (which contain an unsymmetrical allylic
ligand) showed the presence of two species, suggesting a
non-stereoselective coordination of the unsymmetrical
allylic fragment relative to the two distinct halide and
acetonitrile ligands (Scheme 2). The ratio between the
Figure 1. ORTEP drawing of 2d showing 50% thermal ellip-
soids; selected bond distances (ä) and angles (8): Ru(1)
À
À
Br(1) 2.552(6), Ru(1) N(1) 2.077(4), Ru(1) C(14) 2.280(5),
Ru(1) C(15) 2.165(5), Ru(1) C(16) 2.208(4), C(13) C(14)
À
À
À
À
À
1.495(8), C(14) C(15) 1.403(8), C(15) C(16) 1.394(7),
Br(1) Ru(1) N(1) 82.2(1), Br(1) Ru(1) C(16) 81.7(2),
N(1) Ru(1) C(14) 82.7(2), C(13) C(14) C(15) 123.5(5),
C(14) C(15) C(16) 115.8(5); the PF6 anion and the water
molecule are omitted for clarity.
À
À
À
À
À
À
À
À
À
À
Scheme 1. Synthesis of the new complexes 2a f.
836¹ 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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Ruthenium-Catalyzed O-Allylation of Phenols
FULL PAPERS
amount of phenol was used (Table 1). Total conversion
was reached by using an excess of phenol but with a con-
comitant decrease in regioselectivity (Table 1). The
reaction was also achieved on a preparative scale
(3.50 g) to give the allylic ethers 3a and 4a in 78% overall
yield and a 19:1 ratio (3a: 95%, 4a: 5%).
The reaction could be extended to various substituted
phenols such as meta- and para-cresol, 2-chlorophenol,
4-chlorophenol, or 4-methoxyphenol as functionalized
phenols, and afforded the corresponding branched
ethers 3b f with good regioselectivities (Table 1). It is
worth noting that potassium carbonate generated the ar-
yloxide anion in situ, and thus avoided a preliminary
preparation of the nucleophile.
Scheme 2. Simple representation of the two stereoisomers of
2c f as their enantiomeric pairs AA× and BB× (the formation
of 2c f is diastereoselective with respect to the chiral CHR
and CH carbon atoms).
meric pairs arising from a chiral metal center
(Scheme 2).
The coordination of a CH2CHCHPh allylic ligand in
other Cp*Ru(IV) complexes has been depicted as in-
volving a minor contribution of an olefinic coordination
of a formal CH2 CH C(þ)HPh moiety, on the basis of
the observation of close Ru CH2 and Ru CH bond
¼
À
À
À
lengths [2.196(3) ä and 2.197(3) ä, respectively] besides
[8]
À
a longer Ru CHPh bond [2.398(3) ä]. Emphasizing
Scheme 3. Ruthenium-catalyzed synthesis of allyl aryl ethers
from cinnamyl chloride.
that an analogous contribution of a CH2 CH C(þ)HMe
HMe olefinic coordination is at least markedly reduced
¼
À
À
in 2d, the Ru CHMe bond [2.280(5) ä] is slightly longer
À
Ruthenium-Catalyzed Synthesis of Allyl Phenyl
Ethers from Aliphatic Allylic Chlorides
[0.072 vs. 0.202 ä] than the Ru CH2 bond [2.208(4) ä]
À
and a short Ru CH bond [2.165(5) ä] is observed.
To take advantage of the regioselectivity induced by
Ruthenium-Catalyzed Formation of Allyl Aryl Ethers ruthenium catalysis offering an opportunity to develop
from Cinnamyl Chloride and Phenols
a simple access to branched allyl aryl ethers starting
from allylic chlorides, the involvement of aliphatic allyl-
The cationic Ru(IV) complexes 2a f are expected to be ic chlorides in the catalytic process was then investi-
highly electrophilic, but further catalytic involvement gated. The isomeric 3-chloro-1-butene MeCH(Cl)
¼
¼
will obviously require a nucleophilic reactant, which CH CH2, and crotyl chloride MeCH CHCH2Cl both
will be inert towards the free allylic chloride. Although react with phenol and K2CO3 in acetone at reflux to af-
a slow reaction may occur at room temperature, it is wor- ford the corresponding branched and linear phenyl
¼
¼
thy of note that the reaction of allylic chlorides with phe- ethers MeCH(OPh)CH CH2, 5a, and MeCH CHCH2
nols in the presence of K2CO3 requires a thermal activa- OPh, 6a, respectively.[18] We have verified that the reac-
tion. After prolonged heating, cinnamyl chloride is thus tion is sluggish at room temperature, especially with re-
selectively converted to the corresponding linear ether spect to 3-chloro-1-butene. Under our catalytic condi-
[16,17]
¼
PhCH CHCH2OPh.
The opposite regioselectivity tions (vide supra), the reaction of crotyl chloride led to
was observed at room temperature when complex 1 a mixture of 5a and 6a in a 5:1 molar ratio as determined
1
was added as a catalyst to a mixture of cinnamyl chloride by H NMR spectroscopy (Scheme 4). The regioselec-
and K2CO3 in acetonitrile prior to the addition of phe- tivity was enhanced by using acetone instead of acetoni-
nol. Under typical conditions, the addition of phenol trile as a solvent, thus allowing us to reach an 8:1 ratio in
(1.0 to 1.6equivalents) to a mixture of cinnamyl chloride
favor of the branched ether 5a. Crotyl chloride is too vol-
(0.5 mmol), K2CO3 (excess), in 4 mL of acetonitrile in atile to allow a significant determination of the conver-
the presence of 1 (0.015 mmol, 3 mol %) led to the for- sion. On a preparative scale (4 5 g) the 8:1 mixture of
mation of the branched allyl phenyl ether 3a asthe major 5a and 6a was obtained in an overall yield of 68% after
compound (Scheme 3). The consumption of cinnamyl distillation under vacuum and it should be mentioned
chloride (60%) was not complete when an equimolar that the linear ether 6a consisted of a mixture of the trans
Adv. Synth. Catal. 2004, 346, 835 841
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Mbaye D. Mbaye et al.
FULL PAPERS
Table 1.
ArOH
Equivalent[a]
Conversion (%)[b]
Products
Ratio (3: 4)[c]
Phenol
Phenol
Phenol
Phenol
m-Cresol
p-Cresol
2-Chlorophenol
4-Chlorophenol
4-Methoxyphenol
4-Methoxyphenol
1
1.2
1.6100
2
60
90
3a, 4a
3a, 4a
3a, 4a
3a, 4a
3b, 4b
3c, 4c
3d, 4d
3e, 4e
3f, 4f
50: 1
53: 1
42: 1
29: 1
36: 1
38: 1
4: 1
40: 1
36: 1
40: 1
100
100
1
1.6100
1
1.6100
1
100
65
1.6100
3f, 4f
Experimental conditions: catalyst 3 mol %, solvent: MeCN, room temperature, 40 h.
[a]
Equivalent¼ArOH/cinnamyl chloride molar ratio.
[b]
Relative to cinnamyl chloride.
[c]
1
As determined by H NMR spectroscopy.
(very major) and cis (minor) isomers. The involvement ruthenium center. The molecular structure of 2d sug-
of 3-chloro-1-butene instead of crotyl chloride in such gested a less pronounced cationic charge at the RCH al-
a procedure resulted in a gain of regioselectivity lylic center when R¼alkyl than when R¼Ph, in the in-
(12:1). The isomeric chlorohexenes n-PrCH CHCH2 termediate (h3-allyl)Ru(IV) species. This is in agree-
Cl and n-PrCH(Cl)CH CH2 (as a 4:1 mixture) were ment with the observation of a better regioselectivity
¼
¼
also converted under our catalytic conditions into the in favor of the branched isomers when cinnamyl chlor-
phenyl ethers n-PrCH(OPh)CH CH2 5b, and n- ide is compared to crotyl chloride.
PrCH CHCH2OPh 6b, but the regioselectivity was low-
er (1.7:1 in acetonitrile, 2.4:1 in acetone). 3-Chloro-4-
¼
¼
¼
phenyl-1-butene, PhCH2CH(Cl)CH CH2, is readily
available from benzyl bromide and allyl chloride and
was tested under our conditions.[19] Emphasizing that
bulky groups such as n-Pr and PhCH2 disfavor the regio-
selectivity, the phenyl ethers 5c and 6c were formed in a
1.5:1 ratio (in acetonitrile or acetone) but the conver-
sion was found to be complete by 1H NMR spectrosco-
py.
Scheme 5. A plausible mechanism for the ruthenium-cata-
lyzed formation of allyl aryl ethers.
Conclusion
The readily available tris-acetonitrile ruthenium(II)
complex [Cp*(MeCN)3Ru][PF6] 1 is an active catalyst
precursor for the synthesis of allyl aryl ethers starting
from allylic chlorides and phenols and using K2CO3 as
a base. The reaction takes place under mild conditions
at room temperature and provides a regioselective for-
mation of branched products, especially when an arylal-
lylic chloride such as cinnamyl chloride is involved. As a
Scheme 4. Ruthenium-catalyzed synthesis of allyl phenyl
ethers from aliphatic allylic chlorides.
Mechanistic Considerations
From a mechanistic point of view, the addition of an ar- key-step of the catalytic process and accounting for a fa-
yloxide anion to a cationic ruthenium(IV) allylic inter- vored formation of branched products, fast oxidative ad-
mediate is likely involved in the catalytic process dition of allylic halides to the Ru(II) center will generate
(Scheme 5). Such a reductive addition will generate a la- reactive electrophilic (h3-allyl)Ru(IV) intermediates re-
bile olefinic ruthenium(II) intermediate, allowing again lated to the stable [Cp*(allyl)(MeCN)RuX][PF6] com-
oxidative addition of allylic chloride to occur at the plexes.
838
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Ruthenium-Catalyzed O-Allylation of Phenols
FULL PAPERS
(s, 15H, C5Me5), 2.25 (s, 3H, Me), 2.51 (s, 1H, CHH, anti),
Experimental Section
4
2.56(s, 3H, MeCN), 2.71 (s, 1H, CH H, anti), 3.83 (d, J¼
4
3.3 Hz, 1H, CHH, syn), 4.05 (d, J¼3.4 Hz, 1H, CHH, syn);
13C{1H} NMR (CD2Cl2): d¼4.47 (MeCN), 9.65 (C5Me5),
18.90 (Me), 61.90 (CH2), 71.28 (CH2), 107.41 (C5Me5), 113.98
(CMe), 129.93 (MeCN); anal. calcd. for C16H25ClF6NPRu
(512.87): C 37.47, H 4.91, Cl 6.91, N 2.73; found C 37.68, H
5.00, Cl 6.65, N 2.84.
General Remarks
The reactions were performed under an argon atmosphere us-
ing Schlenk-type techniques. Diethyl ether and dichlorome-
thane were distilled after drying according to conventional
methods, whereas HPLC grade acetonitrile, acetone and meth-
anol were used as obtained. Elemental analyses were per-
formed by the Service de Microanalyse du CNRS, Vernaison,
France. NMR spectra were recorded at 297 K on an AC 200
FT Bruker instrument (1H: 200.13, 13C: 50.32 MHz) and refer-
enced internally to the solvent peak. 3-Chloro-4-phenyl-1-bu-
tene was prepared as reported previously.[19] The mixture of
1-chloro-2-hexene and 3-chloro-1-hexene (4:1) was obtained
by reacting trans-3-hexen-1-ol with PCl3.[20] The other allylic
chlorides were commercially available compounds and were
used without further purification. The synthesis of
[Cp*(MeCN)3Ru][PF6] (1) was adapted from previous work
as detailed below.[4,21]
[Cp*(h3-CH2CHCHMe)(MeCN)RuCl][PF6](2c)
From crotyl chloride: To a solution of 1 (2.00 g, 3.96mmol) in
acetonitrile (30 mL), crotyl chloride (1-chloro-2-butene)
(0.60 mL, 6.16 mmol) was added. After being stirred for
10 min, the solution was evaporated under vacuum. The resi-
due was dissolved in dichloromethane (30 mL) and this solu-
tion was covered with diethyl ether (100 mL) to afford orange
crystals. Yield: 1.70 g (84%).
From 3-chloro-1-butene: To
a solution of 1 (2.05 g,
4.06mmol) in acetonitrile (20 mL), 3-chloro-1-butene
(0.60 mL, 5.86 mmol) was added. After being stirred for
10 min, the solution was diluted with dichloromethane
(20 mL) then covered with diethyl ether (120 mL) to afford
large dark-orange crystals. Yield: 1.80 g (86%).
[Cp*(MeCN)3Ru][PF6](1)
A mixture consisting of [Cp*RuCl]4 (12.4 g, 11.4 mmol), KPF6
(8.50 g, 46.2 mmol), and acetonitrile (100 mL) was stirred over-
night and then heated to reflux to be filtered. The hot dark-or-
ange filtrate depositedorange crystals of 1 upon cooling to 08C.
The crystals were collected, then washed with methanol
(20 mL) and diethyl ether (30 mL), and finally dried under vac-
uum. Yield: 16.1 g (70%).
Alternatively, a mixture consisting of [Cp*RuCl2]2, granular
zinc (in excess) and acetonitrile, was stirred overnight to afford
a dark-orange solution. KPF6 was then added and the mixture
was treated as described above.
Solutions in CD2Cl2 and CD3CN were consistent with a mix-
ture of two isomers in a 1:1 and 1.5:1 ratio, respectively, as de-
1
1
termined by H NMR spectroscopy. H NMR (CD2Cl2): d¼
3
1.53 and 1.61 (2 d, J¼6.4 and 6.4 Hz, 3H, MeCH), 1.70 and
1.71 (2 s, 15H, C5Me5), 2.53 and 2.58 (2 s, 3H, MeCN), 2.54
and 2.62 (broad d and d, 3J¼9.0 and 11.5 Hz, 1H, CHH,
anti), 3.33 3.54 (m, 1 H, MeCH), 4.15 and 4.32 (dd and d,
3J¼6.0 and 6.2, J¼0.6Hz, 1H, CH H, syn), 5.06 5.27 (m, 1
4
H, CH); 1H NMR (CD3CN, asterisk marks values for the minor
3
isomer when distinct): d¼1.47* and 1.55 (2 d, J¼6.2* and
6.4 Hz, 3H, MeCH), 1.65* and 1.66 (2 s, 15H, C5Me5), 1.99 (s,
3
3H, MeCN), 2.59* and 2.66 (2 d, J¼10.1* and 10.1 Hz, 1H,
CHH, anti), 3.43 3.61 (m, 1H, MeCH), 4.06* and 4.20 (2 d,
3J¼6.2* and 6.2 Hz, 1H, CHH, syn), 5.04 5.23 (m, 1H, CH);
13C{1H} NMR (CD3CN, asteriskmarks values forthe minor iso-
mer): d¼9.01 and 9.05* (C5Me5), 17.2* and 17.6( MeCH), 62.0*
and 69.9 (CH2), 86.5 and 95.4* (MeCH), 99.0* and 99.3 (CH),
106.2* and 106.7 (C5Me5); anal. calcd. for C16H25ClF6NPRu
(512.87): C 37.47, H 4.91; found C 37.54, H 4.95.
[Cp*(h3-CH2CHCH2)(MeCN)RuCl][PF6]¥1/4CH2Cl2 ¥
H2O (2a)
To a solution of 1 (2.44 g, 4.84 mmol) in acetonitrile (40 mL),
allyl chloride (1.00 mL, 12.3 mmol) was added. After being
stirred for 10 min, the solution was evaporated under vacuum.
The remaining solid was dissolved in dichloromethane (30 mL)
and the solution was then covered with diethyl ether (100 mL)
to afford orange crystals. Yield: 2.40 g (92%); 1H NMR
(CD2Cl2): d¼1.70 (s, 15H, C5Me5), 2.49 (s, 3H, MeCN), 2.61
[Cp*(h3-CH2CHCHMe)(MeCN)RuBr][PF6]¥H2O
(2d)
3
3
(d, J¼10.4 Hz, 1H, CHH, anti), 2.71 (d, J¼10.4 Hz, 1H,
3
4
CHH, anti), 4.17 (dd, J¼6.1, J¼3.1 Hz, 1H, CHH, syn),
3
4
4.33 (dd, J¼6.2, J¼3.1 Hz, 1H, CHH, syn), 5.28 (m, 1H,
CH); 13C{1H} NMR (CD2Cl2): d¼4.65 (MeCN), 9.83 (C5Me5),
65.50 (CH2), 73.96(CH 2), 98.85 (CH), 107.64 (C5Me5), 129.98
(MeCN); anal. calcd. for C15H23ClF6NPRu¥1/4CH2Cl2 ¥H2O
(538.09): C 34.04, H 4.78, Cl 9.88, N 2.60, P 5.76; found C
33.80, H 4.56, Cl 10.56, N 2.69, P 5.96.
Complex 2d was similarly obtained starting from 1 (2.00 g,
3.96mmol) in acetonitrile (30 mL) and crotyl bromide
(0.60 mL, 5.83 mmol). Yield: 1.61 g (71%). Solutions in CD2
Cl2 or CD3CN were consistent with a mixture of two isomers
in a 4:1 ratio as determined by 1H NMR spectroscopy.
1H NMR (CD2Cl2, asterisk marks values for the minor isomer
when distinct): d¼1.59* and 1.60 (2 d, 3J¼6.2* and 6.4 Hz, 3H,
MeCH), 1.76* and 1.77 (2 s, 15H, C5Me5), 2.41 and 2.56* (2 d,
3J¼10.1 and 10.8* Hz, 1H, CHH, anti), 2.55* and 2.60 (2 s,
3H, MeCN), 3.41 3.27 (m, 1H, MeCH), 4.10* and 4.58 (2 d,
3J¼6.2* and 6.2 Hz, 1H, CHH, syn), 5.09 5.25 (m, 1H, CH);
1H NMR (CD3CN, asterisk marks values for the minor isomer
[Cp*(h3-CH2CMeCH2)(MeCN)RuCl][PF6](2b)
Complex 2b was similarly obtained starting from 1 (1.52 g,
3.01 mmol)
and
3-chloro-2-methylpropene
(0.60 mL,
1
3
6.14 mmol). Yield: 1.26 g (82%); H NMR (CD2Cl2): d¼1.71
when distinct): d¼1.54 (d, J¼6.3 Hz, 3H, MeCH), 1.72 (s,
Adv. Synth. Catal. 2004, 346, 835 841
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Mbaye D. Mbaye et al.
FULL PAPERS
15H, C5Me5), 1.99 (s, 3H, MeCN), 2.50 and 2.55* (2 d, 3J¼10.1
and 10.5* Hz, 1H, CHH, anti), 3.33 3.51 (m, 1H, MeCH), 4.01*
and 4.45 (2 d, 3J¼6.1* and 6.3 Hz, 1H, CHH, syn), 5.07 5.21
(m, 1H, CH); 13C{1H} NMR (CD3CN, asterisk marks values
for the minor isomer): d¼9.35 and 9.39* (C5Me5), 17.5 and
19.0* (MeCH), 62.0* and 66.9 (CH2), 86.4 and 94.1*
(MeCH), 98.3* and 98.6(CH), 105.8* and 106.3 ( C5Me5);
anal. calcd. for C16H25BrF6NPRu (575.34): C 33.40, H 4.73, Br
13.89, N 2.43, P 5.38; found C 34.42, H 4.52, Br 13.87, N 2.76,
P 5.10. The high carbon value suggests the loss of the molecule
of water as calcd. for the anhydrous compound C 34.48.
(PhCH), 93.2* and 94.0 (CH), 105.9* and 106.9 (C5Me5),
128.4 131.8 (Ph, CH carbon atoms), 134.1* and 134.9 (Ph,
ipso); anal. calcd. for C21H27ClF6NPRu (574.94): C 43.87, H
4.73, Cl 6.17, N 2.44, P 5.39; found C 43.04, H 4.80, Cl 6.98, N
2.73, P 5.40.
X-ray Crystallographic Study
C16H25BrF6NPRu¥H2O, Mr ¼575.34, crystal size 0.40ꢀ0.32ꢀ
0.28 mm, monoclinic, space group P21/c, Z¼4, a¼8.4097(1)
ä, b¼15.1228(3) ä, c¼17.6318(4) ä, b¼93.595(1)8, V¼
2237.97(7) ä3, dcalcd¥ ¼1.708 g cmÀ3, T¼293(2) K, F(000)¼
1144, Mo-Ka radiation (l¼0.71069 ä), m¼2.612 mmÀ1, 9810
reflections measured in the range 3.078¼q¼27.478, 5098
unique (Rint ¼0.02%) which were used in all calculations. The
sample was studied with a Nonius Kappa CCD diffractometer
with graphite monochromator. The cell parameters were ob-
tained with Denzo and Scalepack.[22] The data collection
(2qmax ¼548, 199 frames via 2.08 w rotation and 20 s per frame,
index ranges 0¼h¼10, 0¼k¼19, À22¼l¼22) gave 33539 re-
flections.[23] The data reduction led to 9810 independent reflec-
tions from which 4230 with I>2s(I) and 248 parameters, R1(all
data)¼0.0569, wR2(all data)¼0.1355, goodness-of-fit on F2 ¼
1.076. The structure was solved with SIR-97 which revealed
the non-hydrogen atoms.[24] After anisotropic refinement,
many hydrogen atoms may be found with Fourier difference
calculations. The whole structure was refined with SHELXL97
by full-matrix least-squares on F2 [x, y, z, bij for Ru, Br, P, F, C, O
[Cp*(h3-CH2CHCHPr-n)(MeCN)RuCl][PF6](2e)
Complex 2e was obtained as above in 68% yield starting from 1
and 1-chloro-2-hexene and 3-chloro-1-hexene as a (4:1) mix-
ture. Solutions in CD2Cl2 and CD3CN are consistent with amix-
ture of two isomers in a 1:1 and 1.5:1 ratio, respectively, as de-
1
1
termined by H NMR spectroscopy. H NMR (CD2Cl2): d¼
1.05 and 1.10 (2 t, 3J¼7.1 and 7.0 Hz, 3H, MeCH2), 1.57 1.82
(m, very broad, 4H, CH2CH2), 1.70 and 1.71 (2 s, 15H, C5
3
Me5), 2.53 and 2.57 (2 s, 3H, MeCN), 2.53 and 2.58 (2 d, J¼
10.2 and 9.9 Hz, 1H, CHH, anti), 3.15 3.38 (m, 1H, n-PrCH),
3
4.19 and 4.35 (dd and d, J¼6.1 and 6.2 Hz, 1H, CHH, syn),
5.08 5.25 (m, 1H, CH); 1H NMR (CD3CN, asterisk marks val-
ues for the minor isomer when distinct) d¼1.01* and 1.06(2 t,
3J¼7.2* and 7.2 Hz, 3H, MeCH2), 1.52 1.79 (m, very broad,
4H, CH2CH2), 1.65* and 1.66 (2 s, 15H, C5Me5), 1.99 (s, 3H,
MeCN), 2.59* and 2.67 (2 d, 3J¼9.9* and 10.1 Hz, 1H, CHH,
2
and N atoms; x, y, z in riding mode for H atoms; w¼1/[s2(F0 )þ
(0.075P)2 þ2.94P] where P¼(F0 þ2Fc2)/3 with the resulting
2
3
anti), 3.24 3.46(m, 1H, n-PrCH), 4.09* and 4.23 (2 d, J¼
R1 ¼0.045, wR2 ¼0.127 and S¼1.076, D1<0.9 eäÀ3; minimum
6.0* and 6.2, 1H, CHH, syn), 5.06
5.22 (m, 1H, CH);
and maximum final electron density: À0.619 and 0.998
13C{1H} NMR (CD3CN, asteriskmarks values for the minor iso-
eäÀ3 [25] ORTEP views were prepared with PLATON98.[26]
.
mer): d¼9.04 and 9.11* (C5Me5), 13.3 and 13.5* (Me), 23.1*
Crystallographic data (excluding structure factors) for the
structure reported in this paper have been deposited with the
Cambridge Crystallographic Data Centre as supplementary
publication no. CCDC-225761. Copies of the data can be ob-
tained free of charge on application to the CCDC, 12 Union
Road, Cambridge CB2 1EZ, U. K. [Fax: (internat.)þ44
1223/336 033; E-mail: deposit@ccdc.cam.ac.uk].
and 23.9 (MeCH2), 34.3* and 34.6(MeCH CH2), 62.4* and
2
70.5 (CH2, allyl), 90.3 and 98.4* (n-PrCH), 98.9 and 99.3
(CH), 106.3* and 106.7 (C5Me5); anal. calcd. for C18H29ClF6
NPRu (540.92): C 39.97, H 5.40, Cl 6.55, N 2.59, P 5.73; found
C 40.10, H 5.50, Cl 6.23, N 2.65, P 5.60.
[Cp*(h3-CH2CHCHPh)(MeCN)RuCl][PF6](2f)
Catalytic Experiments
Complex 2fwas also obtainedin 68% yield as red crystals, start-
ing from 1 and cinnamyl chloride. Solutions in CD2Cl2 or
CD3CN are consistent with a mixture of two isomers in a 3:1
ratio as determined by 1H NMR spectroscopy. 1H NMR (CD2
Cl2, asterisk marks values for the minor isomer when distinct):
d¼1.70* and 1.71 (2 s, 15H, C5Me5), 2.11 and 2.55* (2 s, 3H,
MeCN), 2.78 (d, 3J¼10.1 Hz, 1H, CHH, anti), 4.30* and 4.46
In a typical experiment, a 0.5 mmol sample of allylic chloride
was added to a mixture consisting of K2CO3 (K2CO3/phenol
molar ratio¼1.2, or 1 for aliphatic allylic chlorides), 1
(0.015 mmol) and acetonitrile or acetone (4.0 mL). Then, the
phenol derivative was added and the mixture was stirred at
room temperature for 40 h. The resulting slurry was evaporat-
ed under vacuum and the residue was extracted with dichloro-
methane (20 mL). The collected solution was filtered and the
filtrate was evaporated to leave the crude product that was an-
alyzed by 1H NMR spectroscopy (CDCl3).
3
4
(dd and d, J¼6.5* and 6.4, J¼0.5* Hz, 1H, CHH, syn),
4.55* and 4.60 (dd and d, 3J¼11.0* and 11.2, 4J¼0.5* Hz, 1H,
PhCH), 5.64 5.78* and 5.87 6.01 (2 m, 1H, CH), 7.40 7.68
(m, 5H, Ph); 1H NMR (CD3CN, asterisk marks values for the
minor isomer when distinct): d¼1.66 (s, 15H, C5Me5), 1.99 (s,
3H, MeCN), 2.85* and 2.86(2 d, 3J¼9.7* and 9.6Hz, 1H,
3
CHH, anti), 4.19* and 4.35 (2 d, J¼6.2* and 6.4, 1H, CHH,
1-Phenyl-1-phenoxy-2-propene (3a)
3
syn), 4.62* and 4.64 (2 d, J¼12.2* and 11.2, 1H, PhCH),
5.79* and 5.92 (2 ddd, 3J¼11.8*, 9.9*, 6.4* and 11.1, 9.7,
6.4 Hz, 1H, CH), 7.34 7.64 (m, 5H, Ph); 13C{1H} NMR
(CD3CN, asterisk marks values for the minor isomer when dis-
tinct): d¼9.20 (C5Me5), 59.8* and 67.7 (CH2), 91.4 and 101.2*
A 3.00 mL (21.5 mmol) sample of cinnamyl chloride was added
to a mixture consisting of 4.16g (30.1 mmol, 1.4 equivs.) of K 2
CO3, 0.33 g (0.65 mmol) of 1, and acetonitrile (120 mL). Then,
phenol (2.84 g, 30.2 mmol, 1.4 equivs.) was added and the mix-
840
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Adv. Synth. Catal. 2004, 346, 835 841

Ruthenium-Catalyzed O-Allylation of Phenols
FULL PAPERS
ture was stirred at room temperature for 40 h. The resulting
slurry was evaporated under vacuum and the residue was ex-
tracted with dichloromethane (100 mL) in several parts. The
collected solution was filtered. Small amounts of NaH were
added to the filtrate (to trap residual phenol) until evolution
of gas ceased and the solution was filtered again. The filtrate
was evaporated under vacuum to leave a pale brown oil con-
sisting of a 19:1 mixture of the expected branched 1-phenyl-
1-phenoxy-2-propene and linear aryl ethers, as determined
by 1H NMR spectroscopy.[10] Yield: 3.50 g (78%).
[6] T. Kondo, T. Mitsudo, Curr. Org. Chem. 2002, 6,
1163 1179.
[7] B. M. Trost, P. L. Fraisse, Z. T. Ball, Angew. Chem. Int.
Ed. 2002, 41, 1059 1061.
[8] M. D. Mbaye, B. Demerseman, J.-L. Renaud, L. Toupet,
C. Bruneau, Angew. Chem. Int. Ed. 2003, 42, 5066 5068.
[9] H. Kondo, Y. Yamaguchi, H. Nagashima, Chem. Com-
mun. 2000, 1075 1076.
[10] F. Lopez, T. Ohmura, J. F. Hartwig, J. Am. Chem. Soc.
2003, 125, 3426 3427.
[11] P. A. Evans, D. K. Leahy, J. Am. Chem. Soc. 2000, 122,
5012 5013.
[12] T. Satoh, M. Ikeda, M. Miura, M. Nomura, J. Org. Chem.
1997, 62, 4877 4879.
[13] A. Iourtchenko, D. Sinou, J. Mol. Catal. A 1997, 122,
91 93.
[14] B. M. Trost, H. C. Shen, L. Dong, J.-P. Surivet, J. Am.
Chem. Soc. 2003, 125, 9276 9277.
[15] T. D. Quach, R. A. Batey, Org. Lett. 2003, 5, 1381 1384.
[16] L. Claisen, F. Kremers, F. Roth, E. Tietze, Liebigs Ann.
Chem. 1925, 442, 210 245.
[17] L. Claisen, E. Tietze, Ber. dtsch. chem. Ges. 1926, 59B,
2344 2351.
[18] H. L. Goering, R. R. Jacobson, J. Am. Chem. Soc. 1958,
80, 3277 3285.
[19] M. Julia, J.-N. Verpeaux, T. Zahneisen, Bull. Soc. Chim.
Fr. 1994, 131, 539 554.
1-Methyl-1-phenoxy-2-propene (5a)
From crotyl chloride: A 4.85 mL (49.7 mmol) sample of crotyl
chloride was added to a mixture consisting of 8.23 g
(59.5 mmol) of K2CO3, 0.38 g (0.75 mmol) of 1, and acetone
(100 mL). Phenol (4.68 g, 49.7 mmol) was added and the mix-
ture was stirred at room temperature for 20 h. Then, 0.38 g
(0.75 mmol) of 1 was added again and the mixture was stirred
for another 20 h. The resulting slurry was evaporated under
vacuum and the residue was extracted with dichloromethane
(100 mL) in several parts. After subsequent work-up as above,
the crude oil was distilled under vacuum (bp: 388C/torr)[27] to
obtain a pale-yellow oil. Yield : 5.00 g (68%).
From 3-chloro-1-butene: A 5.00 mL (49.7 mmol) sample of
3-chloro-1-butene was involved instead of crotyl chloride ac-
1
cording to the same procedure. Yield: 4.60 g, 62%. The H
and 13C{1H} NMR spectroscopic data are given elsewhere.[15]
[20] C. D. Hurd, R. W. McNamee, J. Am. Chem. Soc. 1932,
54, 1648 1651.
[21] B. Steinmetz, W. A. Schenk, Organometallics 1999, 18,
943 946.
Acknowledgements
[22] Z. Otwinowski, W. Minor, Processing of X-ray Diffrac-
tion Data Collected in Oscillation Mode, Macromol.Crys-
tallogr. A 1997, 276, 307 326.
The authors are grateful to the EuropeanUnion COST Program
Action D24/0005/02 for support.
[23] NONIUS KappaCCD Software, Nonius BV, Delft, The
Netherlands, 1999.
References
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[25] G. M. Sheldrick, SHELXL97 Program for the Refine-
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[26] A. L. Spek, PLATON A Multipurpose Crystallographic
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[27] F. J. Weigert, W. C. Drinkard, J. Org. Chem. 1973, 38,
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Adv. Synth. Catal. 2004, 346, 835 841
asc.wiley-vch.de
¹ 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
841