Dihydromyrcenol carbonylation catalyzed by palladium-tin precursors: Selectivity of the reaction drawn by the experimental conditions and the co-reactants

Article abstract of DOI:10.1016/S0022-328X(01)01245-1

The methoxycarbonylation of dihydromyrcenol 1 has been carried out in the presence of the catalytic system [PdCl₂(PPh₃)₂] -SnCl₂·2H₂O-2PPh₃. This study shows that it is possible to reduce t

Full text of DOI:10.1016/S0022-328X(01)01245-1

Journal of Organometallic Chemistry 643–644 (2002) 12–18
www.elsevier.com/locate/jorganchem
Dihydromyrcenol carbonylation catalyzed by palladium–tin
precursors: selectivity of the reaction drawn by the experimental
conditions and the co-reactants
Ge´raldine Lenoble, Martine Urrutigo¨ıty, Philippe Kalck *
Laboratoire de Catalyse, Chimie Fine et Polyme`res, Ecole Nationale Supe´rieure des Inge´nieurs en Arts Chimiques et Technologiques,
118 Route de Narbonne, 31077 Toulouse Cedex 04, France
Received 15 May 2001; accepted 31 August 2001
Abstract
The methoxycarbonylation of dihydromyrcenol 1 has been carried out in the presence of the catalytic system [PdCl2(PPh3)2]–
SnCl2·2H2O–2PPh3. This study shows that it is possible to reduce the amounts of isomerization of the terminal double bond and
the dehydration side-reaction of the tertiary alcoholic function. According to the experimental conditions (PCO=40 or 100 bar,
concentration of methanol, experiment duration, temperature) it is possible to orient the reaction towards the three ‘linear’ esters
4, 5, 6, and lactone 8. This latter product has been exclusively obtained when the acidity of the medium is controlled. Nevertheless
it is more difficult to obtain one ester from each others. © 2002 Elsevier Science B.V. All rights reserved.
Keywords: Carbonylation; Hydroesterification; Lactone; Palladium; Terpenes
nation sphere of palladium to become a ligand. How-
ever, it can also promote the migratory insertion of CO
1. Introduction
into the alkyl bond due to its Lewis acidity [3]. Gener-
The alkoxycarbonylation of alkenes is an elegant way
ally the starting material is [PdCl2(PPh3)2] which is of
to produce directly esters or related derivatives like
an easy access; in the presence of SnCl2, it should give
lactones [1] (Scheme 1).
[PdCl(SnCl3)(PPh3)2]. Indeed, it is analogous to
Usually palladium complexes catalyze this reaction
[PtCl(SnCl3)(PPh3)2] which has been isolated and fully
under medium-pressure conditions, and it has been
shown in the early studies that tin dichloride plays a
characterized [3a,4]. Moreover, [PdCl(SnCl3)(PPh3)2]
has been observed in solution by NMR and the tin–
promoting role in this reaction [2]. The exact role of
phosphorus coupling constant measured [5]. Other
SnCl2 is not clear, since, if we transpose the chemistry
of the related platinum complexes where PtꢀSnCl3 is
formed from a PtꢀCl bond, it should enter the coordi-
phosphine or diphosphine ligands have also been used
[6].
During several years, the mechanism of catalysis has
been controversial due to the possibility of a ‘PdꢀH’
route in competition with a PdꢀCOOMe carbomethoxy
route [7]. Several indirect evidences support the hydrido
route [8]. Particularly, during our studies on terpenes
we have intercepted traces of an unsaturated cyclopen-
tenone; it results in a first step from a CH allylic
cleavage in isolimonene by the palladium precursor [9].
Terpenes represent an interesting pool as substrates
since from the C10 framework and the various unsatu-
rations it contains their functionalization is possible.
Thus, the access to oxygenated products is of interest
due to their potential activity in perfumery [10]. We
Scheme 1.
* Corresponding author. Tel.: +33-5-62885656; fax: +33-5-
62885600.
E-mail address: pkalck@ensct.fr (P. Kalck).
0022-328X/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)01245-1

G. Lenoble et al. / Journal of Organometallic Chemistry 643–644 (2002) 12–18
13
Table 1
Reactions of alkoxycarbonylation of dihydromyrcenol 1: [1]/[PdCl2(PPh3)2]=50, methanol=50 mmol
Run
T (°C)
Time (h)
Conversion (%)
Yield (%)
Selectivity of 4–8 (%)
2
3
4
5
6
7
8
1
2
3
4
72
82
92
72
80
72
72
16
16
16
40
16
16
40
87
100
100
100
100
52
15
–
–
–
–
11
11
10
10
4
19
32
41
42
43
3
19
5
3
10
6
8
14
11
3
4
7
2
11
9
4
3
70
89
90
90
96
77
90
30
34
30
40
2
5 a
6 b
7 b
4
10
2
7
27 (52) c
24
–
14
99
1 d
13
39
1 d
Conditions: [PdCl2(PPh3)2]=1 mmol, excess of phosphine=2 mmol, SnCl2·2H2O=2.5 mmol, toluene=25 ml, PCO=40 bar.
a PCO=100 bar.
b methanol=300 mmol.
c Selectivity (%).
d Peak observed by chromatography and considered to be 1% as the method limit.
Scheme 2.
were interested in the methoxycarbonylation of dihy-
dromyrcenol, which contains a terminal CꢁC bond and
a tertiary alcohol function as well, with the aim to
induce the formation of a lactone by a tandem reaction.
This paper deals with the examination of the main
reaction parameters to drive the carbonylation of this
substrate.
of experiments has been done in toluene, as usual [9],
with 50 equivalents of methanol, for fifty equivalents of
dihydromyrcenol. The CO pressure was 40 bar, and the
temperature was ranging between 72 and 92 °C, for 16
h. Table 1 displays the general runs and shows that the
total selectivity in carbonylated products (last column)
varies between 70 and 90%, but can reach 96% at 100
bar (run 5). Scheme 2 shows the various products which
have been formed during this studies. It can be men-
tioned that the addition of anhydrous SnCl2 provides
the same results. However if [PdCl2(PPh3)2] is intro-
duced in the absence of tin chloride, we checked that
the yields were dramatically reduced since the conver-
sion was lowered to 20%.
2. Results and discussion
2.1. General test
The catalytic system introduced in the autoclave is
[PdCl2(PPh3)2] and SnCl2·2H2O, in the presence of an
excess of two equivalents of triphenylphosphine in or-
der to maintain a molar [PPh3]/[Pd] ratio of 4. A series
Significant amounts of compounds 3 and/or 2 were
systematically found after each experiment: 2 results
from an isomerisation reaction which classically in-

14
G. Lenoble et al. / Journal of Organometallic Chemistry 643–644 (2002) 12–18
Direct hydroesterification of 1 produced 5, which can
give 4 by dehydration. Lactone 8 resulted from the
direct cyclization of the acyl intermediate
d
[8b,9b,9c,11,12], which concurrently produced 5 when
methanol reacted instead of the inner alcohol function
(Scheme 3).
The effects of a methanol excess have also been
investigated. Runs 6 and 7 of Table 1 are related to a
molar ratio [MeOH]/[1] of 6. The rate of the reaction
decreased significantly as the conversion are 87% for
run 1, and 52% for run 6. The main product obtained
in this latter run was compound 6 with a 52% selectiv-
ity; poor yields in the other products can be noted.
Increasing the time to 40 h (run 7) resulted in profound
modifications in the various selectivities. The conver-
sion was almost complete and 39% of compound 5 were
obtained. Simultaneously, 14% of lactone 8 were pro-
duced. In our opinion, the higher concentration of
methanol induced a faster neutralization of HCl. It
could occur through the formation of CH3Cl, which
was removed in the gas phase when the 40 bar of CO
were depressurized, and thus not detected, or it could
be associated with methanol through hydrogen bonds.
In the absence of an acidic medium, products 5 and 8
were favored.
Scheme 3.
volves the coordination of 1 to a palladium hydride
species, followed by a b-H elimination. Only isomer 2
has been detected by GC–MS and 1H-NMR. Com-
pound 3 has been formed by dehydration of 1, pre-
sumably due to the presence of an acidic medium
produced by the loss of HCl when the palladium hy-
dride species was produced [9]. GC–MS experiments
have shown that several isomers were formed: as the
methylpropenyl fragment was observed, only the termi-
nal carbon–carbon double bond should have migrated
towards internal positions; only isomer 3 is represented.
This isomer was the starting material for the hydroes-
terification or hydroxycarbonylation giving rise to the
unsaturated ester 4 and acid 7, respectively. The ester 6
resulted presumably directly from 4 or 3, depending on
the relative order of electophilic addition of methanol
and carbonylation, however, the methylether of 1 has
not been detected. Nevertheless, formation of 6 from 5
with methanol in acid medium could be envisioned.
When the temperature was raised from 72 to 82 and
92 °C, no more compound 2 was found in the solution,
because the dehydration process was faster (the yields
of 4 and 7 increased) and some internal isomers of 3
were still produced from 2. It is important to underline
that only the isomer of 3 as represented on Scheme 2
reacted to produce 4, 6 and 7, as terminal esters or acid
and all others branched esters have not been detected.
Similarly, reduced amounts of 2, and even 4 can result
from an increase in the reaction time (run 4) or in the
CO pressure (100 bar, run 5); parallel greater quantities
of 7, and in a lesser extent of 4 can be noted.
2.2. Esters 4, 5, and 6
In order to direct the carbonylation reaction towards
the esters, we have increased the concentration in
methanol. The results are displayed in Tables 2 and 3.
In each case, the molar [substrate]/[Pd] ratio has been
increased to 100; Table 2 refers to a [methanol]/[Pd]
ratio of 100, whereas Table 3 concerns a ratio of 300.
In general, the three esters were obtained simulta-
neously most of the time. Run 8 shows that they can be
produced roughly in the absence of the other carbony-
lated products; the presence of large amounts of isomer
2 reduced the selectivity in esters to 66%. It is worth
mentioning that the selectivity in the ether–ester 6
Table 2
Reactions of alkoxycarbonylation of dihydromyrcenol 1: [1]/[PdCl2(PPh3)2]=100, methanol=100 mmol
Run
T (°C) Time (h) Conversion (%) Yield (%)
Selectivity of 4–8 (%)
2
3
4
5
6
7
8
8
9
72
84
72
80
16
16
40
16
39
100
96
12 (34) a 1 b
2
28
4
24
18 (46) a 1 b
20 12
20 (21) a 24 (25) a 27 (28) a 12
23 21 24 12
1 b
4
2
66
88
89
87
–
3
–
12
8
13
10
11 c
100
7
Conditions: [PdCl2(PPh3)2]=1 mmol, excess of phosphine=2 mmol, SnCl2·2H2O=2.5 mmol, toluene=25 ml, PCO=40 bar.
a Selectivity (%).
b Peak observed by chromatography and considered to be 1% as the method limit.
c PCO=100 bar.

G. Lenoble et al. / Journal of Organometallic Chemistry 643–644 (2002) 12–18
15
Table 3
Reactions of alkoxycarbonylation of dihydromyrcenol 1: [1]/[PdCl2(PPh3)2]=100, methanol=300 mmol
Run T (°C)
Time (h)
Conversion (%)
Yield (%)
Selectivity of
4–8 (%)
2
3
4
5
6
7
8
12
13
14
15
16
72
66
72
84
92
16
40
40
40
40
16
43
35
74
100
100
88
14 (37) a 1 b
1 b
–
7
30
31
12
3
13
3
–
–
11
–
4
63
74
70
92
84
76
8
19
–
1 b
3
23 (66) a
18 (24) a 22 (30) a 1 b
8
39
11
13
36
8
5
2
–
9
16
12
1 b
17 c 80
25 (28) a 27 (31) a 1 b
2
Conditions: [PdCl2(PPh3)2]=1 mmol, excess of phosphine=2 mmol, SnCl2·2H2O=2.5 mmol, toluene=25 ml, PCO=40 bar.
a Selectivity (%).
b Peak observed by chromatography and considered to be 1% as the method limit.
c PCO=100 bar.
shows the higher value of all our experiments and
reached 46%.
reaction times (run 4). Of course, if methanol is not
introduced, the production of the acid 7 or lactone 8
would be favored. At 100 bar and for 16 h ([1]/[Pd]=
100) we obtained 92% of 7 for a 100% conversion rate,
absence of 8 and 8% of isomer 3 [12]. We never observed
the saturated acid, which would correspond to the
hydroxycarbonylation of 1.
The experiments carried out with an excess of
methanol revealed the formation of some significant
amounts of lactone 8, presumably due to some neutral-
ization of HCl. In order to promote the cyclization of
species d, and to have a great selectivity in 8, we
introduced molecular sieves to remove HCl as soon as
it was formed, and the amounts of water co-produced as
well. We have previously reported [12] that such an
addition allowed to reach a selectivity in 8 as high as
98%. Thus, at 40 bar and for a conversion of 60% after
40 h, only traces of isomer 3 were detected.
In conclusion, carbonylation of dihydromyrcenol 1,
catalyzed by [PdCl2(PPh3)2]/SnCl2·2H2O/2PPh3, oc-
curred readily under medium pressure conditions to give
three esters, one acid and a lactone. Modifications of the
experimental conditions allowed us to direct the reac-
tion towards one carbonylated product. However, the
main problem which appeared was the acidity of the
medium due to the formation of HCl when the palla-
dium hydride species was initiated. The addition of
molecular sieves trapped this acidity and directed the
reaction to the lactone 8. An excess of methanol induced
the formation of the three esters, although it was
difficult to privilege one of them. All the observations
we have done in this study are summarized in Scheme 4.
From run 13, we can conclude that the high concen-
tration in methanol together with the relatively low
temperature adopted for the experiment allowed a good
selectivity (66%) in the expected ester 5. That means that
the activation energy for the transformation d“5 is
lower than d“8.
However, the increase of the temperature had dra-
matic effects. From run 16, it appears that extensive
dehydration has taken place. Thus, even if an excess of
methanol reduced the negative effect of HCl, the pres-
ence of an acidic medium at the early stage of the
reaction induced the formation of 3, and thus 4 and 6,
which results from the methoxylation of 4. Due to the
relatively important concentration of methanol, few
quantities of acid 7 were formed.
The general trend for higher pressures (runs 5, 11 and
17) is, as expected, an increase in the proportion of
carbonylated products. For instance, in run 11, com-
parable quantities (ca. 23%) of 4, 5, or 6 were obtained.
Of course, in the presence of a methanol excess, ether 6
was a little bit more abundant.
Longer reaction times induced higher conversion
rates. When a 100% yield was reached, isomer 2 was no
more present, because it can give the dehydration
product 3, or after transfer of hydride from a PdꢀH
species the back isomerization, although it is slow,
towards the terminal CꢀC double bond. This phe-
nomenon is induced by the steric hindrance of the
coordination sphere of palladium and the bulkiness of
PPh3 is important.
2.3. Unsaturated acid 7 and lactone 8
3. Experimental
As already described in Section 2.1, abundant quanti-
ties of ester 4 and acid 7 can be produced in the presence
of few amounts of methanol and at high pressure (run
5), or at higher temperature (run 3), or for longer
3.1. General
1
The H-, 13C- and 31P-NMR spectra were recorded
with CDCl3 solutions containing TMS as internal stan-

16
G. Lenoble et al. / Journal of Organometallic Chemistry 643–644 (2002) 12–18
dard on a Bruker AM250 spectrometer operating at
250.13, 62.90 and 101.26 MHz, respectively. Data are
reported as follows: chemical shift in ppm (l), multi-
plicity (s=singlet, d=doublet, t=triplet, q=quartet,
and m=multiplet), coupling constant in Hz (J), inte-
gration, and assignation. IR spectra were obtained on a
Perkin–Elmer 1710 spectrometer; absorptions are re-
ported in cm−1. Analytical GC was carried out on a
Carlo Erba MFC 500 apparatus equipped with a
Econo-Cap FFAP (30 m; 0.53 mm; 1.2 mm) capillary
column and a flame ionization detector. Products were
identified by GC–MS on a Perkin–Elmer QMass 910
Mass Spectrometer (MS) with ionization voltage of 70
eV, with a Crompack CP WAX 52 CB (50 m; 0.32 mm;
0.2 mm) polar column. Elemental analyses were per-
formed by the Analytic Laboratory of ENSIACET.
Column chromatography was performed with SiO2
(Merck).
3.3. Typical procedure
A mixture of 0.702 g (1 mmol) of dichlorobis(t-
riphenylphosphine)palladium(II), 0.474 g (2.5 mmol) of
hydrated tin(II) chloride and 0.524 g (2 mmol) of
triphenylphosphine was introduced into a 250 ml stain-
less steel autoclave with mechanical stirring. A dinitro-
gen-saturated mixture of 7.814 g of dihydromyrcenol
(50 mmol) and 1.602 g of methanol (50 mmol) in 25 ml
toluene was introduced into the evacuated autoclave by
aspiration. It was heated to 72 °C under 40 bar of
carbon monoxide at constant pressure. After 16 h, the
autoclave was cooled and then slowly depressurized.
The yellow–orange reaction mixture was analyzed by
gas chromatography.
After the catalytic reaction, the organometallic com-
pounds and the phosphine excess were separated from
the crude solution by adding CCl4. The deeply colored
oily layer was decanted. After concentration by rotary
evaporation, the oily residue was purified by column
chromatography on silica gel.
3.2. Materials
[PdCl2(PPh3)2] was prepared according to the litera-
ture [13], (yield 95%), 31P{1H}-NMR (CDCl3): lp 23.47
(s), IR w=1481, 1436, 1099, 746, 693. Solvents with
high purity (toluene, methanol) have been used as
received, as well as dihydromyrcenol (DRT SA), SnCl2
(Aldrich\99%), SnCl2·2H2O (Prolabo 98%), triphenyl-
phosphine (Aldrich 99%).
3.4. Characterization of the products
3.4.1. Methyl 4,8-dimethylnon-7-enoate (4)
Incolore oil; (eluent: heptane–dichloromethane–
1
ethyl acetate=75/12.5/12.5); H-NMR (CDCl3): l 5.01
(t, n.d., 1H, H7), 3.58 (s, 3H, CH3 12), 2.25 (m, 2H,
H5), 1.88 (m, 1H, H4), 1.60 (s, 3H, CH3 9), 1.52 (s, 3H,
Scheme 4.

G. Lenoble et al. / Journal of Organometallic Chemistry 643–644 (2002) 12–18
17
CH3 10), 1.34–0.82 (m, 6H, H2, H3 and H6), 0.80 (d,
J=6 Hz, 3H, CH3 11); 13C-NMR (CDCl3): l 174.4
(C1), 131.1 (C7), 124.6 (C8), 51.3 (C12), 36.7 (C5), 32.0,
31.9 and 31.8 (C2, C3 and C4), 25.6 and 25.4 (C9 and
C10), 19.1 (C11), 17.5 (C6); IR (neat): 1712 (CꢁO); MS,
m/z (relative intensity, %): 199 (1), 198 [M+, 2], 183
(11), 74 (100), 69 (100), 41 (51). Anal. Calc. for
C12H22O2: C, 72.68; H, 11.18; O, 16.14. Found: C,
71.85; H, 11.80; O, 16.44%.
2H, H7), 1.91 (m, 1H, H4), 1.63–1.49 (m, 6H, H3, H5
and H6), 1.35 (s, 6H, CH3 10 and CH3 9), 1.16 (m, 2H,
H2), 0.80 (d, J=5.8 Hz, 3H, CH3 11); 13C-NMR
(CDCl3): l 173.5 (C1), 82.3 (C8), 41.1 (C7), 37.0 (C5),
33.4 and 32.3 (C2, C3 and C4), 26.1 (C10 and C9), 21.3
(C11), 19.3 (C6);); IR (neat): 1729 (CꢁO); MS, m/z
(relative intensity, %): 185 [M+1, 3], 184 (M, 6), 97
(19), 43 (34), 41 (100). Anal. Calc. for C11H20O2: C,
71.70; H, 10.94; O, 17.36. Found: C, 70.89; H, 11.72; O,
16.59%.
3.4.2. Methyl 4,8-dimethyl-8-hydroxynonanoate (5)
Incolore oil; (eluent: heptane–dichloromethane–
ethyl acetate=90/5/5); 1H-NMR (CDCl3): l 3.53 (s,
3H, CH3 12), 2.18 (m, 2H, H5), 2.09 (m, 1H, H4), 1.53
(m, 2H, H3), 1.28 (m, 4H, H6 and H7), 1.14 (t, n.d.,
2H, H2), 1.07 (s, 6H, CH3 9 and CH3 10), 0.75 (d,
J=6.1 Hz, 3H, CH3 11); 13C-NMR (CDCl3): l 174.2
(C1), 70.4 (C8), 51.2 (C12), 43.8 (C7), 37.0 (C5), 32.1,
31.6 and 31.5 (C2, C3 and C4), 28.9 and 28.8 (C9 and
C10), 21.4 (C11), 19.0 (C6); IR (neat): 1729 (CꢁO); MS,
m/z (relative intensity, %): 217 [M+1, 5], 201 (12), 199
(100), 87 (100), 74 (14), 59 (100), 43 (81). Anal. Calc.
for C12H24O3: C, 66.63; H, 11.18; O, 22.19. Found: C,
66.29; H, 10.78; O, 22.37%.
Acknowledgements
We thank the Ministe`re de l’Education Nationale de
la Recherche et de la Technologie for a Research Grant
(Lenoble G.). Acknowledgments are also due to Engel-
hard-CLAL for a generous loan of palladium, and
DRT SA for the gift of dihydromyrcenol.
References
[1] (a) G. Consiglio, M. Marchetti, Chimia 30 (1976) 26;
(b) T. Hiyama, N. Wakasa, T. Kusumoto, Synlett (1991) 569;
(c) B. El Ali, H. Alper, J. Mol. Catal. A: Chem. 96 (1995) 197.
[2] (a) J.F. Knifton, J. Org. Chem. 41 (1976) 2885;
(b) G. Cavinato, L. Toniolo, J. Mol. Catal. 10 (1981) 161;
(c) I. Cipres, J. Jenck, Ph. Kalck, J. Mol. Catal. 58 (1990) 387;
(d) L.L. da Rocha, A.O. Dias, E.N. dos Santos, R. Augusti,
E.V. Gusevskaya, J. Mol. Catal. A: Chem. 132 (1998) 213;
(e) M.C. Bonnet, A.L. Monteiro, I. Tkatchenko, J. Mol. Catal.
A: Chem. 143 (1999) 131;
(f) M.C. Bonnet, N. Carmona, I. Tkatchenko, J. Mol. Catal. A:
Chem. 143 (1999) 181.
[3] (a) M. Gomez, G. Muller, D. Sainz, J. Sales, Organometallics
10 (1991) 4036;
(b) E.V. Gusevskaya, E.N. dos Santos, R. Augusti, A.O. Dias,
C.M. Foca, J. Mol. Catal. A: Chem. 152 (2000) 15.
[4] J.V. Kingston, G.R. Scollary, J. Chem. Soc. (A) (1971) 3765.
[5] K.H.A. Ostoja Starzewski, P.S. Pregosin, H. Ru¨egger, Helv.
Chim. Acta 65 (1982) 785.
3.4.3. Methyl 4,8-dimethyl-8-methoxynonanoate (6)
Orange oil; (eluent: heptane–dichloromethane–ethyl
acetate=90/5/5); 1H-NMR (CDCl3): l 3.59 (s, 3H,
CH3 12), 3.10 (s, 3H, CH3 13), 2.25 (m, 1H, H4),
1.63–1.31 (m, 10H, H2, H3, H5, H6 and H7), 1.06 (s,
6H, CH3 9 and CH3 10), 0.81 (d, J=6.1 Hz, 3H, CH3
11); 13C-NMR (CDCl3): l 174.2 (C1), 74.3 (C8), 51.2
(C12), 48.8 (C13), 40.0 (C7), 37.1 (C5), 31.7 and 31.6
(C4, C3 and C2), 24.7 (C9 and C10), 21.0 (C11), 19.0
(C6); IR (neat): 1730 (CꢁO); MS, m/z (relative inten-
sity, %): 231 [M+1,1], 199 (1), 74 (11), 73 (100), 41 (41).
Anal. Calc. for C13H26O3: C, 67.79; H, 11.38; O, 20.84.
Found: C, 67.57; H, 10.87; O, 19.46%.
3.4.4. Acid 4,8-dimethylnon-7-enoique (7)
Incolore oil; (eluent: heptane–dichloromethane–
ethyl acetate=90/5/5); H-NMR (CDCl3): l 10.79 (m,
[6] (a) S. Naili, J.F. Carpentier, F. Agbossou, A. Mortreux, G.
Nowogrocki, J.P. Wignacourt, New J. Chem. 21 (1997) 919;
(b) L.L. da Rocha, A.O. Dias, E.N. dos Santos, R. Augusti,
E.V. Gusevskaya, J. Mol. Catal. A: Chem. 132 (1998) 213.
[7] (a) G. Cavinato, L. Toniolo, Chimia 33 (1979) 286;
(b) R. Bardi, A. del Pra, A.M. Piazzesi, L. Toniolo, Inorg.
Chimi. Acta 35 (1979) L345;
(c) R. Bertani, G. Cavinato, L. Toniolo, G. Vasapollo, J. Mol.
Catal. 84 (1993) 165.
[8] (a) B. El Ali, H. Alper, J. Mol. Catal. 77 (1992) 7;
(b) K. Kudo, K. Mitsuhashi, S. Mori, K. Komatsu, N. Sugita,
Chem. Lett. (1993) 1615;
1
1H, OH), 5.05 (t, J=6 Hz, 1H, H7), 2.31 (m, 2H, H5),
1.95 (m, 1H, H4), 1.64 (s, 3H, CH3 9), 1.57 (s, 3H, CH3
10), 1.5-1.1 (m, 6H, H2, H3 and H6), 0.86 (d, J=6.1
Hz, 3H, CH3 11); 13C-NMR (CDCl3): l 180.8 (C1),
131.1 (C7), 124.4 (C8), 36.5 (C5), 31.7 and 31.2 (C2, C3
and C4), 25.5 and 25.2 (C9 and C10), 19.0 (C11), 14.5
(C6); IR (neat): 1709 (CꢁO); MS, m/z (relative inten-
sity, %): 185 [M+1, 2], 124 (3), 69 (100), 41 (99). Anal.
Calc. for C11H20O2: C, 71.70; H, 10.94; O, 17.36.
Found: C, 71.91; H, 11.40; O, 16.69%.
(c) K. Kudo, Y. Oida, K. Mitsuhashi, S. Mori, K. Komatsu,
N. Sugita, Bull. Chem. Soc. Jpn. 69 (1996) 1337.
[9] (a) T. Chenal, I. Cipres, J. Jenck, Ph. Kalck, Y. Peres, J. Mol.
Catal. 78 (1993) 351;
3.4.5. 4,8,8-trimethyloctano-8-lactone (8)
(b) T. Chenal, R. Naigre, I. Cipres, Ph. Kalck, J.C. Daran,
Incolore oil; (eluent: heptane–dichloromethane–
J. Vaissermann, J. Chem. Soc. Chem. Commun.
747;
9 (1993)
ethyl acetate=75/15/10); 1H-NMR (CDCl3): l 2.16 (m,

18
G. Lenoble et al. / Journal of Organometallic Chemistry 643–644 (2002) 12–18
(c) R. Naigre, T. Chenal, I. Cipres, Ph. Kalck, J.C. Daran, J.
Vaissermann, J. Organomet. Chem. 480 (1994) 91.
Daran, Ph. Kalck, Tetrahedron: Asymmetry 10 (1999)
929.
[10] See for instance: S. Akutagawa, in: E.N. Jacobsen, A. Pfaltz, H.
Yamamoto (Eds.), Comprehensive Asymmetric Catalysis,
Springer–Verlag, Berlin, 1999, p. 813.
[12] G. Lenoble, M. Urrutigo¨ıty, Ph. Kalck, Tetrahedron Lett. 42
(2001) 3697.
[13] D.R. Coulson, L.C. Satek, S.O. Orim, Inorg. Synth. 13 (1972)
121.
[11] G. Lenoble, R. Naigre, T. Chenal, M. Urrutigo¨ıty, J.C.