Ligand control of the cobalt-catalysed 1,4-hydrovinylation reaction

Article abstract of DOI:10.1055/s-0032-1316796

The application of cobalt catalysts to the hydrovinylation of unsymmetrical alkenes and 1,3-dienes was investigated using modular phosphine-phosphite ligands to evaluate the influence of the ligands on the regioselectivity of the reaction. While a ligand with a TADDOL subunit (SchmalzPhos) gave the best results for the β-4 regioisomer, the corresponding BINOL-derived ligand gave predominantly the β-1 regioisomer. The application of (E)-2-methylpenta-1,3-diene in combination with the (nonracemic) BINOL-derived ligand generated the β-4 regioisomer in excellent yields and very high regioselectivities for a number of terminal alkenes bearing various functional groups. In one case, the enantiomeric excess of a chiral product, i.e. a 3,5-dimethylhexa-1,4-diene derivative, was determined by chiral RP-HPLC to be 78% ee. Georg Thieme Verlag KG · Stuttgart · New York.

Full text of DOI:10.1055/s-0032-1316796

3534▌
PAPER
paper
Ligand Control of the Cobalt-Catalysed 1,4-Hydrovinylation Reaction
Ligand-Controlled Cobalt-Catalysed 1,4-Hydrovinylation Reaction
Marion Arndt,a Mehmet Dindaroğlu,b Hans-Günther Schmalz,b Gerhard Hilt*a
a
Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35043 Marburg, Germany
E-mail: Hilt@chemie.uni-marburg.de; Fax +49(6421)2825677
b
Department für Chemie, Universität zu Köln, Greinstr. 4, 50939 Cologne, Germany
Received: 17.09.2012; Accepted: 18.09.2012
moderately regioselective bond formation. Therefore, this
study used only simple and readily available 2-substituted
1,3-dienes, such as isoprene and myrcene, as unsymmet-
rical 1,3-dienes.
Abstract: The application of cobalt catalysts to the hydrovinylation
of unsymmetrical alkenes and 1,3-dienes was investigated using
modular phosphine-phosphite ligands to evaluate the influence of
the ligands on the regioselectivity of the reaction. While a ligand
with a TADDOL subunit (SchmalzPhos) gave the best results for
the β-4 regioisomer, the corresponding BINOL-derived ligand gave
predominantly the β-1 regioisomer. The application of (E)-2-meth-
ylpenta-1,3-diene in combination with the (nonracemic) BINOL-
derived ligand generated the β-4 regioisomer in excellent yields and
very high regioselectivities for a number of terminal alkenes bear-
ing various functional groups. In one case, the enantiomeric excess
of a chiral product, i.e. a 3,5-dimethylhexa-1,4-diene derivative,
was determined by chiral RP-HPLC to be 78% ee.
In this study, we investigated the performance of different
ligands in the 1,4-hydrovinylation reaction between two
unsymmetrical components. The work was triggered by
the observation that the hydrovinylation of terminal al-
kenes utilising a cobalt complex with the SchmalzPhos
ligand4 L1 (Figure 1) gave excellent results for cobalt-
catalysed carbon–carbon bond formation at the β-carbon
of the donor component with 2,3-dimethylbuta-1,3-diene
as a symmetrical acceptor diene.5 In the case of an unsym-
metrical 1,3-diene, such as 2, we were interested in gener-
ating either of the β-type products 3 or 4 selectively.
Key words: alkene, catalysis, cobalt, diene, 1,4-hydrovinylation
1,2-Hydrovinylation and 1,4-hydrovinylation are atom-
economic reactions for the generation of a new carbon–
carbon bond under mild reaction conditions utilising var-
ious catalyst systems and various transition metals.1 In the
past, cobalt-catalysed 1,4-hydrovinylation reactions were
developed to control the site of formation of the new car-
bon–carbon bond when terminal alkenes were applied.2
The hitherto unsolved problem of the reaction becomes
evident when a terminal double bond and an unsymmetri-
cal 1,3-diene are involved. In these cases, the site of for-
mation not only of the carbon–carbon bond in the alkene
donor component 1, α- or β-position, but also in the 1,3-
diene acceptor component 2, C1 or C4, has to be con-
trolled (Scheme 1). When 2-substituted 1,3-dienes, such
as 2, are utilised, up to four possible products 3–6 can be
envisaged, without taking additional E/Z isomers into
consideration.
In order to examine the feasibility of using the cobalt–L1
system for the conversion of sterically more congested
symmetrical 1,3-dienes, we generated 2,3-dipropylbuta-
1,3-diene (7) in situ from oct-4-yne and ethene through ru-
thenium-catalysed enyne metathesis. Then, 7 was reacted
with 4-allylveratrole and diethyl allylmalonate, respec-
tively, under standard reaction conditions (Scheme 2). In
both reactions, the desired products 8a and 8b were isolat-
ed in good yields as single regioisomers (>99:1), with the
formation of the new carbon–carbon bond taking place at
the β-carbon of the donor components.
Grubbs II, ethene (7 bar)
CH2Cl2, 60 °C, 6 h
R
R
CoBr2(L1), Zn, ZnI2
+
CH2Cl2, r.t., 16 h
R1
R2 R1
8
7
67%
69%
8a R = CH(CO2Et)2
8b R = (3,4-MeO)2C6H3
R1
R2
1
4
R2
α
β
1,4-hydrovinylation
3 (β-4)
5 (α-4)
4 (β-1)
6 (α-1)
+
R2
2
1
Scheme 2 1,4-Hydrovinylation of two terminal alkenes with 7
acceptor
donor
R1
R1
R2
These results illustrate that the 1,4-hydrovinylation of ter-
minal double bonds is also highly regioselective when a
sterically more hindered acceptor component is em-
ployed.
Scheme 1 Formation of possible isomers via 1,4-hydrovinylation
As shown in our earlier study,3 variation of substituents in
the 2- and 3-positions of the acceptor diene gave only
In the second stage of the investigation, various Schmalz-
Phos-type ligands were examined in order to evaluate
their ability to control the selective formation of regioiso-
mers in a cobalt-catalysed hydrovinylation reaction. A
number of ligands were studied, but, besides L1, only bi-
SYNTHESIS 2012, 44, 3534–3542
Advanced online publication: 02.10.2012
DOI: 10.1055/s-0032-1316796; Art ID: SS-2012-Z0725-OP
© Georg Thieme Verlag Stuttgart · New York
0
0
3
9
-
7
8
8
1
1
4
3
7
-
2
1
0
X

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Ligand-Controlled Cobalt-Catalysed 1,4-Hydrovinylation Reaction
3535
phenol-derived ligand L2 and binaphthol-derived ligand action conditions as constant as possible (Scheme 3). The
L3 gave acceptable results.6
crude product mixtures 9–12 were filtered through a small
plug of silica gel and the ratios of regioisomers were de-
termined by GC. The products 9–12 were obtained by
flash column chromatography whereupon the isomers
were inseparable.
Ph
O
O
O
P
PPh2
R1
R2
R1
CoBr2(L1–L3)
(5–10 mol%)
R2
Ph
Ph
Ph
R1
R2
9
10
O
+
O
O
O
O
O
O
O
O
=
R2
Zn, ZnI2, CH2Cl2
r.t. or 40 °C, 16–48 h
2
1
O
L1
L2
L3
R1
R1
R2
Ph
11
12
Figure 1 Ligands applied in the cobalt-catalysed 1,4-hydrovinyl-
ation of unsymmetrical 1,3-dienes
Scheme 3 Cobalt-catalysed hydrovinylation of unsymmetrical start-
ing materials utilising different ligands L1–L3
Utilising unsymmetrical acceptor dienes, a number of ter-
minal alkenes 1 were selected as reaction partners, and
only the ligand structure was altered, keeping the other re-
The results of these cobalt-catalysed 1,4-hydrovinylation
reactions are summarized in Table 1.
Table 1 Results of the Cobalt-Catalysed 1,4-Hydrovinylation of Terminal Alkenes with 2-Substituted 1,3-Dienes
Entry
Ligand Products (9/10/11/12)
Yield
(%)
Ratio
(9/10/11/12)
EtO2C
EtO2C
EtO2C
EtO2C
10a
12a
1
2
3
L1
L2
L3
94
33
72
72:19:5:4
10:66:11:13
24:62:3:11
9a
EtO2C
EtO2C
EtO2C
11a
EtO2C
EtO2C
EtO2C
10b
12b
9b
4
L1
75
50:50:0:0
EtO2C
EtO2C
11b
MeO
MeO
MeO
MeO
10c
12c
9c
5
L1
86
67:11:9:13
MeO
MeO
MeO
11c
MeO
EtO2C
EtO2C
EtO2C
CO2Et
EtO2C
EtO2C
6
7
L2
L3
85
94
16:72:6:6
20:71:2:7
EtO2C
EtO2C
9d
10d
11d
12d
iBuO2C
iBuO2C
iBuO2C
iBuO2C
8
L3
94
18:77:1:4
9e
10e
11e
12e
© Georg Thieme Verlag Stuttgart · New York
Synthesis 2012, 44, 3534–3542

3536
M. Arndt et al.
PAPER
Table 1 Results of the Cobalt-Catalysed 1,4-Hydrovinylation of Terminal Alkenes with 2-Substituted 1,3-Dienes
Entry
Ligand Products (9/10/11/12)
Yield
(%)
Ratio
(9/10/11/12)
9
L3
93
3:97:0:0
9f
10f
11f
12f
AcO
BnO
AcO
AcO
AcO
BnO
10
11
12
L3
95
96
58
8:87:2:3
9g
10g
11g
12g
BnO
BnO
L3
5:66:13:16
8:91:<1:<1
9h
10h
11h
12h
HO
HO
HO
HO
L3
9i
10i
11i
12i
The products of type 9, such as 9a, were obtained predom- period of six hours. The results of these reactions are sum-
inantly utilising the SchmalzPhos ligand L1 (entries 1 and marised in Table 2.
5) while products of type 10 were formed as a minor com-
ponent. In addition to these products, the products of car-
R
R
bon–carbon bond formation at the α-carbon of the alkene
component, such as 11a,c and 12a,c, were detected. How-
ever, using ethyl acrylate (entry 4) gave a 1:1 mixture of
9b and 10b while the corresponding products 11b and 12b
were not formed.
CoBr2(L3)
(5–10 mol%)
1
4
R
15
17
16
+
Zn, ZnI2, CH2Cl2
r.t. or 40 °C, 6–22 h
14
13
R
R
Changing the TADDOL-type motif to a biphenol subunit
(ligand L2/3) altered the regioselectivity considerably.
Applying diethyl allylmalonate (entries 2, 3 and 6, 7), re-
gioisomers of type 10 were formed predominantly. Of
particular interest was the formation of product 10f (entry
9), which was generated in excellent yield and very good
regioselectivity (ratio 9f/10f, 3:97). This is in sharp con-
trast with the results of Ritter and co-workers, who pre-
dominantly obtained 9f (79%, ratio 9f/10f, 84:16)
utilising an iron-based catalyst system.7 The application
of protected as well as unprotected allylic alcohol also
gave interesting results. Not only could the unprotected
allylic alcohol be used for the formation of 10i in an ac-
ceptable yield and with good regioselectivity (entry 12),
but also allyl acetate could be used to give 10g in excellent
yield and good selectivity (entry 10). These products ex-
hibit sufficient purity to be of use in successive chemical
transformations.
18
(17/18 not observed)
Scheme 4 Application of 14 as an unsymmetrical 1,3-diene in hy-
drovinylation reactions
Fortunately, when ligand L3 was used only the two regio-
isomers of type 15 and 16 were observed and the regiose-
lectivity in favour of the β-4 products 15 was excellent in
almost all cases. For a number of different alkenes the 1,4-
hydrovinylation products of type 15 were obtained in ex-
cellent yields. These building blocks with a broad range of
functional groups will allow a number of successive trans-
formations in the future and could be of great value.
Besides another version of an asymmetric Diels–Alder re-
action,9 this is the second case where a stereogenic centre
was formed during the course of a cobalt-catalysed carbon–
carbon bond formation. The application of S-configured
ligand L3 in this cobalt-catalysed 1,4-hydrovinylation re-
action led to the formation of 15d in 78% ee [(R)-L3 gave
15d with 82% ee].Unfortunately, this derivative was the
only example where the enantiomers could be separated
by chiral RP-HPLC; for this reason enantiomeric excesses
for the other products cannot be reported herein. All prod-
ucts of type 15 were oily substances and no crystalline
Finally, we were interested whether an additional substit-
uent in the 1,3-diene would improve the regioselectivity
of carbon–carbon bond formation. For this purpose, ter-
minal alkenes 13 were reacted with (E)-2-methylpenta-
1,3-diene (14) under similar reaction conditions (Scheme
4) to afford the desired 1,4-diene products 15–18.8 In or-
der to obtain good results, i.e. to avoid dimerisation of the
diene component, the diene 14 was added slowly over a
Synthesis 2012, 44, 3534–3542
© Georg Thieme Verlag Stuttgart · New York

PAPER
Ligand-Controlled Cobalt-Catalysed 1,4-Hydrovinylation Reaction
3537
All reagents were used as purchased from commercial suppliers
without further purification. All reactions were carried out using
standard Schlenk techniques under dry argon. Solvents were puri-
fied and dried according to conventional methods prior to use. The
Table 2 Regioselective Synthesis of Products of Type 15 via Cobalt-
Catalysed Hydrovinylation in the Presence of Ligand L3
Entry
Product 15
Yield
(%)
Ratio
1
following equipment or materials were used: H and 13C NMR:
(15/16)
AVANCE 300 (300 MHz for 1H and 75 MHz for 13C), an AVANCE
500 (500 MHz for 1H and 125 MHz for 13C), or an AVANCE 600
(600 MHz for 1H and 150 MHz for 13C). 31P NMR: AVANCE 500
(202.5 MHz for 31P). Chemical shifts: relative to residual resonanc-
es of solvents [1H: δ = 7.26 (CHCl3); 13C: δ = 77.0 (CDCl3); 31P:
δ = 0 (85% H3PO4) as external standard]. IR spectroscopy: Bruker
Alpha P (FTIR) or a Bruker IFS 88 (FTIR) spectrophotometer (sam-
ples as film or neat). EI-MS: Finnigan MAT 95S (70 eV). ESI-
HRMS: Thermo Fisher Scientific LTQ-FT. GC analysis: Shimadzu
GC-2010 Plus Gas Chromatograph. GC-MS: Agilent 6890 gas
chromatograph with a Hewlett Packard 5973 mass detector. Chiral
RP-HPLC: Agilent 1200 Series HPLC System using a Daicel Chi-
ralpak IA column (250 × 4.6 mm); solvent A: 0.1% TFA (aq), sol-
vent B: MeCN (flow rate 0.5 mL/min, column temperature 40 °C,
UV absorption detected at 254 nm). Chromatographic separations:
Macherey-Nagel Silica 60 (0.040–0.063 mm, 230–400 mesh
ASTM). TLC: Merck TLC plates (Silica 60, F254).
iBuO2C
EtO2C
1
2
3
78
80
93
>99:1
>99:1
>99:1
15a
15b
EtO2C
MeO
15c
MeO
O
N
4
98
>99:1
15d
O
O
O
5
6
53
45
>99:1
15e
15f
6-[3-(Diphenylphosphino)biphenyl-2-yloxy]diben-
zo[d,f][1,3,2]dioxaphosphepine (L2)
In a flame-dried Schlenk flask under argon, 2-(boranatodiphe-
nylphosphanyl)-6-phenylphenol6 (184 mg, 0.50 mmol, 1.0 equiv)
and DABCO (453 mg, 4.00 mmol, 8.0 equiv) were dissolved in
CH2Cl2 (3.5 mL). The resulting soln was stirred for 10 min at r.t.,
then cooled to 0 °C and 2 M PCl3 in CH2Cl2 (0.28 mL, 0.56 mmol,
1.1 equiv) was added dropwise via syringe over 30 min. The mix-
ture was stirred for 30 min at this temperature, warmed to r.t., and
stirred overnight. The milky suspension was cooled to 0 °C and a
soln of 2,2′-biphenol (103 mg, 0.55 mmol, 1.1 equiv) in CH2Cl2
(2.2 mL) was added slowly over 30 min. After stirring for 30 min at
0 °C, the mixture was allowed to warm to r.t. and stirring was con-
tinued for a further 16 h. The mixture was filtered through a small
plug of silica gel (pentane–EtOAc, 5:1) and the solvent was evapo-
rated to give the crude product. Purification by column chromatog-
raphy (pentane–EtOAc, 40:1 → 30:1 → 20:1) gave the product (141
mg, 0.25 mmol, 50%) as a white foam; Rf = 0.32 (pentane–EtOAc,
30:1).
>99:1a
AcO
BnO
PhO
HO
7
99
32
63
97
96:4
96:4
>99:1
91:9
15g
8
15h
15i
9
10
15j
a In this reaction, cobalt catalyst (20 mol%) and Zn powder and ZnI2
(40 mol%) were used.
IR (neat): 3056, 1497, 1475, 1435, 1404, 1182, 1090, 909, 870, 850,
763, 732, 697 cm–1.
1H NMR (500 MHz, CDCl3): δ = 7.53–7.47 (m, 2 H, Har), 7.47–
7.33 (m, 16 H, Har), 7.24–7.12 (m, 5 H, Har), 6.93–6.86 (m, 1 H, Har),
6.79–6.72 (m, 2 H, Har).
31P NMR (202.5 MHz, CDCl3): δ = 144.22 [d, J = 42.4 Hz,
P(OR)3], –16.79 (d, J = 42.2 Hz, PPh2).
HRMS (ESI): m/z [M + Na]+ calcd for C36H26O3P2Na: 591.1249;
found: 591.1246.
product could be generated to determine the absolute ste-
reochemistry of products of type 15.
In conclusion, we were able to identify ligand designs that
have potential for further optimisation to generate the de-
sired regioisomers β-4 and β-1 in good-to-excellent re-
gioselectivities. Interesting results were obtained using
styrene as the alkene component yielding the β-1 regioiso-
mer 10f almost exclusively. Another factor we encoun-
tered was the choice of the acceptor diene, choosing a
more complex starting material, such as 14, gave the β-4
regioisomer of the 1,4-hydrovinylation products of type
15 in excellent yields and with excellent regioselectivities.
Many functional groups were accepted and very interest-
ing building blocks were generated. The enantiomeric ex-
cess was determined for one product to be around 80% ee.
The search for the right combination of ligands and start-
ing materials has not ended, but seems to have taken an-
other step in the right direction.
Characterization of the ligand by 13C NMR was not accomplished
due to the complexity of the spectra resulting from P–C coupling.
Synthesis of Cobalt Complexes CoBr2(L)
The ligand (1.0 equiv) was dissolved under an argon atmosphere in
THF (ca. 0.04 M). Anhyd CoBr2 (1.0 equiv) was added and the sus-
pension was stirred at r.t. overnight. The solvent was removed under
reduced pressure, and the complex was dried under high vacuum
and used without further characterisation.
Enyne Metathesis and Subsequent 1,4-Hydrovinylation; Gener-
al Procedure
Oct-4-yne (72 mg, 0.65 mmol, 1.3 equiv) and Grubbs II catalyst (16
mg, 0.02 mmol, 3 mol%) were dissolved in CH2Cl2 (1 mL) and re-
acted with ethene (7 bar) in a glass autoclave at 60 °C for 6 h. Then
argon was bubbled through the soln to remove excess ethene. The
soln was subsequently transferred to a sealed tube. CoBr2(L1) (26
© Georg Thieme Verlag Stuttgart · New York
Synthesis 2012, 44, 3534–3542

3538
M. Arndt et al.
PAPER
mg, 0.03 mmol, 5 mol%), Zn powder (4 mg, 0.05 mmol, 10 mol%),
anhyd ZnI2 (16 mg, 0.05 mmol, 10 mol%), and the alkene (0.50
mmol, 1.0 equiv) were added under an argon atmosphere. The mix-
ture was stirred at r.t. for 16 h and filtered through a small plug of
silica gel (pentane–Et2O, 1:1). The solvent was removed and the
residue was purified by column chromatography (silica gel).
column chromatography (silica gel). The ratios of the regioisomers
were determined by 1H NMR spectroscopy or GC analysis.
Diethyl 2-[(2E,5E)-6,10-Dimethylundeca-2,5,9-trienyl]malo-
nate (9a), Diethyl 2-[(2E,5Z)-5-Ethylidene-9-methyldeca-2,8-di-
enyl]malonate (10a), Diethyl (E)-2-(5,9-Dimethyl-2-methylene-
deca-4,8-dienyl)malonate (11a), and Diethyl (Z)-2-(4-Ethyl-
idene-8-methyl-2-methylenenon-7-enyl)malonate (12a)
Diethyl 2-[(2E,5E)-6-Methyl-5-propylnona-2,5-dienyl]malo-
nate (8a)
After purification by column chromatography (pentane–EtOAc,
40:1), the product (113 mg, 67%) was obtained as a yellow oil;
Rf = 0.22 (pentane–EtOAc, 40:1).
Precatalyst: CoBr2(L1). After purification by column chromatogra-
phy (pentane–EtOAc, 50:1
→ 20:1), the product (ratio
9a/10a/11a/12a, 72:19:5:4; 79 mg, 94%) was obtained as a yellow
oil; Rf = 0.10 (pentane–EtOAc, 50:1).
IR (neat): 2973, 2918, 1733, 1443, 1371, 1261, 1225, 1147, 1096,
1032, 970, 858, 802 cm–1.
IR (neat): 2959, 2931, 2868, 1733, 1459, 1371, 1331, 1259, 1225,
1151, 1034, 970, 860, 790 cm–1.
1H NMR (300 MHz, CDCl3): δ (9a) = 5.57–5.29 (m, 2 H, Holef),
5.14–5.02 (m, 2 H, Holef), 4.18 (q, J = 7.1 Hz, 4 H, OCH2), 3.36 (t,
J = 7.6 Hz, 1 H, CH), 2.67 (dd, J = 13.5, 6.5 Hz, 2 H, CH2), 2.61–
2.52 (m, 2 H, CH2), 2.12–1.86 (m, 4 H, CH2), 1.67 (s, 3 H, CH3),
1.59 (s, 3 H, CH3), 1.57 (s, 3 H, CH3), 1.25 (t, J = 7.1 Hz, 6 H, CH3).
13C NMR (75 MHz, CDCl3): δ (9a) = 169.0 (C=O), 136.2 (Cq,olef),
132.2 (Colef), 131.3 (Cq,olef), 125.2 (Colef), 124.2 (Colef), 121.6 (Colef),
61.2 (OCH2), 52.2 (CH), 39.7 (CH2), 31.8 (CH2), 31.0 (CH2), 26.7
(CH2), 25.6 (CH3), 17.6 (CH3), 15.9 (CH3), 14.1 (CH3).
MS (EI, 70 eV): m/z (%) (9a) = 336 (1) [M]+, 293 (2), 245 (2), 214
(2), 193 (4), 176 (20), 161 (13), 147 (27), 133 (29), 123 (99), 107
(91), 91 (33), 79 (46), 69 (100).
HRMS (ESI): m/z [M]+ calcd for C20H32O4: 336.2301; found:
336.2300.
1H NMR (300 MHz, CDCl3): δ = 5.45 (dt, J = 15.2, 6.1 Hz, 1 H,
Holef), 5.31 (dt, J = 15.2, 6.7 Hz, 1 H, Holef), 4.173 (q, J = 7.2 Hz, 2
H, OCH2), 4.166 (q, J = 7.1 Hz, 2 H, OCH2), 3.35 (t, J = 7.6 Hz, 1
H, CH), 2.66 (d, J = 6.0 Hz, 2 H, CH2), 2.57 (ddd, J = 7.5, 6.6,
0.8 Hz, 2 H, CH2), 2.05–1.86 (m, 4 H, CH2), 1.58 (s, 3 H, CH3),
1.45–1.20 (m, 4 H, CH2), 1.25 (t, J = 7.1 Hz, 6 H, CH3), 0.88 (t,
J = 7.3 Hz, 3 H, CH3), 0.86 (t, J = 7.3 Hz, 3 H, CH3).
13C NMR (75 MHz, CDCl3): δ = 169.0 (C=O), 131.7 (Colef), 130.5
(Cq,olef), 130.2 (Cq,olef), 125.2 (Colef), 61.2 (OCH2), 52.4 (CH), 36.3
(CH2), 35.4 (CH2), 34.2 (CH2), 31.8 (CH2), 22.0 (CH2), 21.7 (CH2),
17.9 (CH3), 14.3 (CH3), 14.15 (CH3), 14.06 (CH3).
MS (EI, 70 eV): m/z (%) = 338 (2) [M]+, 275 (1), 264 (1), 247 (4),
221 (5), 203 (4), 189 (2), 178 (25), 161 (7), 149 (16), 135 (100), 121
(9), 107 (23), 93 (39), 79 (22).
HRMS (EI): m/z [M]+ calcd for C20H34O4: 338.2457; found:
338.2463.
Ethyl (2E,5E)-6,10-Dimethylundeca-2,5,9-trienoate (9b) and
Ethyl (2E,5Z)-5-Ethylidene-9-methyldeca-2,8-dienoate (10b)
Precatalyst: CoBr2(L1). After purification by column chromatogra-
phy (pentane–Et2O, 50:1 → 20:1), the product (ratio 9b/10b, 50:50;
44 mg, 75%) was obtained as a yellow oil; Rf = 0.14 (pentane–Et2O,
50:1).
1,2-Dimethoxy-4-[(2E,5E)-6-methyl-5-propylnona-2,5-di-
enyl]benzene (8b)
After purification by column chromatography (pentane–Et2O,
20:1), the product (100 mg, 69%) was obtained as a yellow oil;
Rf = 0.18 (pentane–Et2O, 20:1).
IR (neat): 2974, 2920, 2858, 1719, 1650, 1445, 1320, 1265, 1162,
1094, 1041, 983, 836 cm–1.
IR (neat): 2956, 2929, 2867, 2837, 1591, 1512, 1459, 1376, 1261,
1232, 1144, 1030, 969, 852, 803, 761, 630 cm–1.
1H NMR (300 MHz, CDCl3): δ (9b) = 7.02–6.82 (m, 1 H, Holef),
5.80 (d, J = 15.5 Hz, 1 H, Holef), 5.15 (t, J = 7.2 Hz, 1 H, Holef),
5.12–5.02 (m, 1 H, Holef), 4.17 (q, J = 7.1 Hz, 2 H, OCH2), 2.96–
2.38 (m, 2 H, CH2), 2.16–1.91 (m, 4 H, CH2), 1.68 (d, J = 3.2 Hz, 3
H, CH3), 1.63–1.55 (m, 6 H, CH3), 1.28 (t, J = 7.1 Hz, 3 H, CH3).
1H NMR (300 MHz, CDCl3): δ (10b) = 7.02–6.82 (m, 1 H, Holef),
5.80 (d, J = 15.5 Hz, 1 H, Holef), 5.38 (q, J = 6.7 Hz, 1 H, Holef),
5.12–5.02 (m, 1 H, Holef), 4.17 (q, J = 7.1 Hz, 2 H, OCH2), 2.96–
2.38 (m, 2 H, CH2), 2.16–1.91 (m, 4 H, CH2), 1.68 (d, J = 3.2 Hz, 3
H, CH3), 1.63–1.55 (m, 6 H, CH3), 1.28 (t, J = 7.1 Hz, 3 H, CH3).
1H NMR (300 MHz, CDCl3): δ = 6.84–6.75 (m, 1 H, Har), 6.75–
6.67 (m, 2 H, Har), 5.61–5.37 (m, 2 H, Holef), 3.86 (s, 6 H, OCH3),
3.29 (d, J = 6.1 Hz, 2 H, CH2), 2.75 (d, J = 5.6 Hz, 2 H, CH2), 2.07–
1.94 (m, 4 H, CH2), 1.64 (s, 3 H, CH3), 1.47–1.28 (m, 4 H, CH2),
0.89 (t, J = 7.3 Hz, 3 H, CH3), 0.88 (t, J = 7.3 Hz, 3 H, CH3).
13C NMR (75 MHz, CDCl3): δ = 148.8 (Cq,ar), 147.2 (Cq,ar), 133.8
(Cq), 130.9 (Cq), 129.91 (Cq), 129.89 (Colef), 128.8 (Colef), 120.2
(Car), 111.7 (Car), 111.2 (Car), 55.9 (OCH3), 55.7 (OCH3), 38.5
(CH2), 36.3 (CH2), 35.5 (CH2), 34.3 (CH2), 22.1 (CH2), 21.7 (CH2),
17.9 (CH3), 14.3 (CH3), 14.1 (CH3).
13C NMR (75 MHz, CDCl3): δ (9b, 10b) = 166.8, 166.7 (C=O9b,
MS (EI, 70 eV): m/z (%) = 316 (22) [M]+, 273 (1), 245 (9), 217 (1),
203 (5), 189 (4), 177 (16), 164 (21), 151 (100), 135 (4), 123 (4), 115
(6), 107 (10), 91 (10), 79 (12).
HRMS (EI): m/z [M]+ calcd for C21H32O2: 316.2402; found:
316.2400.
C=O10b), 147.7, 146.5 (Colef,9b, Colef,10b), 138.4 (Cq,olef,9b), 135.5
(Cq,olef,10b), 131.6 (Cq,olef,9b, Cq,olef,10b), 124.01, 124.00 (Colef,9b
,
Colef,10b), 121.6 (Colef,10b), 121.4 (Colef,10b), 121.0 (Colef,9b), 118.9
(Colef,9b), 60.13, 60.08 (OCH2,9b, OCH2,10b), 39.6 (CH2,9b), 37.2
(CH2,10b), 33.1 (CH2,10b), 30.6 (CH2,9b), 26.7 (CH2,10b), 26.5
(CH2,9b), 25.6 (CH3,9b, CH3,10b), 17.7 (CH3,9b, CH3,10b), 16.0
(CH3,9b), 14.3 (CH3,9b, CH3,10b), 13.3 (CH3,10b).
MS (EI, 70 eV): m/z (%) = 236 (1) [M]+, 221 (2), 194 (6), 180 (3),
163 (4), 153 (3), 147 (7), 139 (15), 123 (19), 107 (14), 95 (38), 88
(8), 79 (22), 69 (100).
Cobalt-Catalysed 1,4-Hydrovinylation; General Procedure
CoBr2(L) (5–10 mol%), Zn powder (10–20 mol%), and anhyd ZnI2
(10–20 mol%) were suspended in anhyd CH2Cl2 (0.5 mL) under an
argon atmosphere in a flame-dried Schlenk tube fitted with a Teflon
screw cap. The terminal alkene (0.25 mmol, 1.0 equiv) and the bu-
tadiene (0.30–0.38 mmol, 1.2–1.5 equiv) were added and the mix-
ture was stirred at r.t. or 40 °C until complete conversion of the
alkene (monitored by GC/MS, 16–48 h). The mixture was filtered
through a short pad of silica gel (pentane–Et2O). The solvent was re-
moved under reduced pressure and the residue was purified by flash
HRMS (EI): m/z [M]+ calcd for C15H24O2: 236.1776; found:
236.1770.
The analytical data for 9b are consistent with those in the litera-
ture.10
Synthesis 2012, 44, 3534–3542
© Georg Thieme Verlag Stuttgart · New York

PAPER
Ligand-Controlled Cobalt-Catalysed 1,4-Hydrovinylation Reaction
3539
4-[(2E,5E)-6,10-Dimethylundeca-2,5,9-trienyl]-1,2-dimethoxy-
benzene (9c), 4-[(2E,5Z)-5-Ethylidene-9-methyldeca-2,8-di-
enyl]-1,2-dimethoxybenzene (10c), (E)-4-(5,9-Dimethyl-2-
methylenedeca-4,8-dienyl)-1,2-dimethoxybenzene (11c), and
(Z)-4-(4-Ethylidene-8-methyl-2-methylenenon-7-enyl)-1,2-di-
methoxybenzene (12c)
Precatalyst: CoBr2(L1). After purification by column chromatogra-
phy (pentane–t-BuOMe, 30:1 → 10:1), the product (ratio
9c/10c/11c/12c, 67:11:9:13; 67 mg, 86%) was obtained as a yellow
oil; Rf = 0.15 (pentane–t-BuOMe, 30:1).
1H NMR (300 MHz, CDCl3): δ (10e) = 5.63–5.41 (m, 2 H, Holef),
5.26 (q, J = 6.7 Hz, 1 H, Holef), 3.86 (d, J = 6.7 Hz, 2 H, OCH2), 3.04
(d, J = 5.9 Hz, 2 H, CH2), 2.74 (d, J = 5.6 Hz, 2 H, CH2), 1.99–1.84
(m, 1 H, CH), 1.67–1.62 (m, 3 H, CH3), 1.59–1.53 (m, 3 H, CH3),
0.92 (d, J = 6.7 Hz, 6 H, CH3).
13C NMR (75 MHz, CDCl3): δ (10e) = 172.1 (C=O), 133.8 (Cq,olef),
131.5 (Colef), 122.5 (Colef), 119.8 (Colef), 70.6 (OCH2), 38.1 (CH2),
34.7 (CH2), 27.7 (CH), 23.3 (CH3), 19.0 (CH3), 13.2 (CH3).
MS (EI, 70 eV): m/z (%) (10e) = 210 (31) [M]+, 195 (1), 154 (51),
IR (neat): 2962, 2911, 2836, 1591, 1512, 1445, 1260, 1232, 1143,
1029, 969, 849, 803, 760, 635 cm–1.
137 (12), 125 (4), 109 (100), 94 (77), 79 (47), 67 (57), 57 (99).
HRMS (EI): m/z [M]+ calcd for C13H22O2: 210.1620; found:
1H NMR (500 MHz, CDCl3): δ (9c) = 6.80 (d, J = 7.8 Hz, 1 H, Har),
6.75–6.69 (m, 2 H, Har), 5.63–5.53 (m, 1 H, Holef), 5.53–5.44 (m, 1
H, Holef), 5.17 (tdd, J = 7.3, 2.5, 1.3 Hz, 1 H, Holef), 5.10–5.05 (m, 1
H, Holef), 3.87 (s, 3 H, OCH3), 3.86 (s, 3 H, OCH3), 3.28 (d,
J = 6.2 Hz, 2 H, CH2), 2.80–2.68 (m, 2 H, CH2), 2.14–1.98 (m, 4 H,
CH2), 1.69–1.65 (m, 3 H, CH3), 1.61 (s, 3 H, CH3), 1.60 (s, 3 H,
CH3).
210.1630.
(E)-(5-Methylhexa-1,4-dienyl)benzene (9f) and [(1E,4Z)-4-
Methylhexa-1,4-dienyl]benzene (10f)
Precatalyst: CoBr2(L3). After purification by column chromatogra-
phy (pentane), the product (ratio 9f/10f, 3:97; 40 mg, 93%) was ob-
tained as a colourless oil; Rf = 0.52 (pentane).
IR (film): 3062, 3030, 2979, 2930, 1724, 1626, 1601, 1495, 1452,
1381, 1159, 1116, 1071, 971, 752, 699 cm–1.
1H NMR (300 MHz, CDCl3): δ (10f) = 7.46–7.28 (m, 4 H, Har),
7.28–7.17 (m, 1 H, Har), 6.45 (d, J = 15.7 Hz, 1 H, Holef), 6.29–6.12
(m, 1 H, Holef), 5.45–5.32 (m, 1 H, Holef), 3.03–2.92 (m, 2 H, CH2),
1.83–1.73 (m, 3 H, CH3), 1.73–1.63 (m, 3 H, CH3).
13C NMR (125 MHz, CDCl3): δ (9c) = 148.8 (Cq,ar), 147.3 (Cq,ar),
136.0 (Cq), 133.7 (Cq), 131.4 (Cq), 130.3 (Colef), 128.9 (Colef), 124.3
(Car/Colef), 122.1 (Car/Colef), 120.2 (Car/Colef), 111.9 (Car), 111.2
(Car), 55.9 (OCH3), 55.8 (OCH3), 39.7 (CH2), 38.5 (CH2), 31.0
(CH2/CH3), 26.7 (CH2/CH3), 25.6 (CH2/CH3), 17.6 (CH3), 16.0
(CH3).
MS (EI, 70 eV): m/z (%) (9c) = 314 (14) [M]+, 189 (18), 177 (16),
159 (9), 151 (100), 138 (4), 123 (23), 115 (8), 107 (13), 91 (13), 79
(15), 69 (40).
13C NMR (75 MHz, CDCl3): δ (10f) = 137.8 (Cq,ar), 133.8 (Cq,olef),
130.3 (Colef), 128.4 (Car), 127.9 (Colef), 126.8 (Car), 126.0 (Car),
120.1 (Colef), 35.2 (CH2), 23.5 (CH3), 13.3 (CH3).
HRMS (EI): m/z [M]+ calcd for C21H30O2: 314.2246; found:
314.2253.
MS (EI, 70 eV): m/z (%) (10f) = 172 (52) [M]+, 157 (81), 143 (98),
129 (100), 115 (84), 104 (33), 91 (70), 79 (29).
HRMS (EI): m/z [M]+ calcd for C13H16: 172.1252; found: 172.1252.
Diethyl (E)-2-(6-Methylhepta-2,5-dienyl)malonate (9d), Diethyl
2-[(2E,5Z)-5-Methylhepta-2,5-dienyl]malonate (10d), Diethyl 2-
(5-Methyl-2-methylenehex-4-enyl)malonate (11d), and Diethyl
(Z)-2-(4-Methyl-2-methylenehex-4-enyl)malonate (12d)
Precatalyst: CoBr2(L3). After purification by column chromatogra-
phy (pentane–EtOAc, 30:1), the product (ratio 9d/10d/11d/12d,
20:71:2:7; 63 mg, 94%) was obtained as a colourless oil; Rf = 0.38
(pentane–EtOAc, 30:1).
(E)-6-Methylhepta-2,5-dienyl Acetate (9g), (2E,5Z)-5-Methyl-
hepta-2,5-dienyl Acetate (10g), 5-Methyl-2-methylenehex-4-
enyl Acetate (11g), and (Z)-4-Methyl-2-methylenehex-4-enyl
Acetate (12g)
Precatalyst: CoBr2(L3). After purification by column chromatogra-
phy (pentane–Et2O, 30:1), the product (ratio 9g/10g/11g/12g,
8:87:2:3; 40 mg, 95%) was obtained as a colourless oil; Rf = 0.18
(pentane–Et2O, 30:1).
IR (film): 2982, 2934, 1734, 1446, 1371, 1334, 1265, 1231, 1178,
1152, 1034, 971, 859, 670 cm–1.
IR (film): 2969, 2930, 1743, 1446, 1383, 1364, 1233, 1027, 970,
829 cm–1.
1H NMR (300 MHz, CDCl3): δ (10g) = 5.81–5.63 (m, 1 H, Holef),
5.63–5.48 (m, 1 H, Holef), 5.36–5.20 (m, 1 H, Holef), 4.51 (d, J = 5.7
Hz, 2 H, OCH2), 2.77 (d, J = 5.6 Hz, 2 H, CH2), 2.05 (s, 3 H, CH3),
1.65 (s, 3 H, CH3), 1.57 (d, J = 6.3 Hz, 3 H, CH3).
13C NMR (75 MHz, CDCl3): δ (10g) = 170.8 (C=O), 134.9 (Cq,olef),
133.2 (Colef), 124.5 (Colef), 120.2 (Colef), 65.0 (OCH2), 34.5 (CH2),
23.3 (CH3), 21.0 (CH3), 13.2 (CH3).
1H NMR (300 MHz, CDCl3): δ (10d) = 5.53–5.30 (m, 2 H, Holef),
5.27–5.17 (m, 1 H, Holef), 4.17 (q, J = 7.1 Hz, 4 H, OCH2), 3.36 (t,
J = 7.6 Hz, 1 H, CH), 2.67 (d, J = 5.7 Hz, 2 H, CH2), 2.63–2.51 (m,
2 H, CH2), 1.63–1.59 (m, 3 H, CH3), 1.56–1.50 (m, 3 H, CH3), 1.24
(t, J = 7.1 Hz, 6 H, CH3).
13C NMR (75 MHz, CDCl3): δ (10d) = 169.0 (C=O), 133.9 (Cq,olef),
130.7 (Colef), 126.0 (Colef), 119.6 (Colef), 61.2 (OCH2), 52.3 (CH),
34.7 (CH2), 31.7 (CH2), 23.2 (CH3), 14.0 (CH3), 13.1 (CH3).
MS (EI, 70 eV): m/z (%) (10d) = 268 (2) [M]+, 223 (3), 205 (1), 194
(1), 177 (11), 161 (4), 149 (4), 133 (6), 121 (14), 108 (91), 93 (100),
79 (16).
HRMS (EI): m/z [M]+ calcd for C15H24O4: 268.1675; found:
268.1682.
MS (EI, 70 eV): m/z (%) (10g) = 125 (<1), 108 (36), 105 (1), 97 (7),
93 (100), 82 (2), 79 (23), 70 (3), 67 (15).
HRMS (EI): m/z = 168; intensity was too low for HRMS measure-
ment.
(E)-[(6-Methylhepta-2,5-dienyloxy)methyl]benzene (9h),
{[(2E,5Z)-5-Methylhepta-2,5-dienyloxy]methyl}benzene (10h),
[(5-Methyl-2-methylenehex-4-enyloxy)methyl]benzene (11h),
and (Z)-[(4-Methyl-2-methylenehex-4-enyloxy)methyl]benzene
(12h)
Precatalyst: CoBr2(L3). After purification by column chromatogra-
phy (pentane–Et2O, 50:1), the product (ratio 9h/10h/11h/12h,
5:66:13:16; 52 mg, 96%) was obtained as a colourless oil; Rf = 0.21
(pentane–Et2O, 50:1) (9h/10h).
Isobutyl (E)-7-Methylocta-3,6-dienoate (9e), Isobutyl (3E,6Z)-
6-Methylocta-3,6-dienoate (10e), Isobutyl 6-Methyl-3-methyl-
enehept-5-enoate (11e), and Isobutyl (Z)-5-Methyl-3-methyl-
enehept-5-enoate (12e)
Precatalyst: CoBr2(L3). After purification by column chromatogra-
phy (pentane–Et2O, 50:1), the product (ratio 9e/10e/11e/12e,
18:77:1:4; 50 mg, 94%) was obtained as a colourless oil; Rf = 0.23
(pentane–Et2O, 50:1).
IR (film): 3064, 3030, 2967, 2927, 2855, 1721, 1667, 1496, 1453,
1376, 1361, 1116, 1095, 1028, 970, 736, 698 cm–1.
IR (film) (9h, 10h): 3032, 2965, 2930, 2876, 2729, 1740, 1470,
1378, 1348, 1306, 1261, 1151, 1001, 968, 824 cm–1.
© Georg Thieme Verlag Stuttgart · New York
Synthesis 2012, 44, 3534–3542

3540
M. Arndt et al.
PAPER
1H NMR (300 MHz, CDCl3): δ (10h) = 7.41–7.19 (m, 5 H, Har),
5.76–5.52 (m, 2 H, Holef), 5.34–5.20 (m, 1 H, Holef), 4.49 (s, 2 H,
OCH2), 4.02–3.93 (m, 2 H, OCH2), 2.82–2.70 (m, 2 H, CH2), 1.70–
1.63 (m, 3 H, CH3), 1.61–1.52 (m, 3 H, CH3).
13C NMR (75 MHz, CDCl3): δ (10h) = 138.5 (Cq,ar), 133.7 (Cq,olef),
131.6 (Colef), 128.3 (Car), 127.7 (Car), 127.5 (Car), 127.0 (Colef),
119.9 (Colef), 71.8 (OCH2), 70.8 (OCH2), 34.5 (CH2), 23.4 (CH3),
13.2 (CH3).
HRMS (EI): m/z [M]+ calcd for C14H24O2: 224.1776; found:
224.1779.
Diethyl (E)-2-(4,6-Dimethylhepta-2,5-dienyl)malonate (15b)
After purification by column chromatography (pentane–EtOAc,
30:1), the product (ratio 15b/16b, >99:1; 56 mg, 80%) was obtained
as a colourless oil; Rf = 0.23 (pentane–EtOAc, 30:1).
IR (neat): 2969, 2927, 2870, 1733, 1446, 1371, 1264, 1225, 1149,
1034, 971, 856 cm–1.
1H NMR (300 MHz, CDCl3): δ = 5.44 (dd, J = 15.3, 6.3 Hz, 1 H,
MS (EI, 70 eV): m/z (%) (10h) = 172 (<1), 159 (1), 146 (2), 125 (3),
108 (13), 91 (100), 79 (14), 65 (13).
H
olef), 5.30 (dtd, J = 15.3, 6.8, 1.0 Hz, 1 H, Holef), 4.95–4.85 (m, 1
HRMS (EI): m/z = 216; intensity was too low for HRMS measure-
ment.
H, Holef), 4.17 (q, J = 7.1 Hz, 4 H, OCH2), 3.35 (t, J = 7.6 Hz, 1 H,
CH), 3.04–2.88 (m, 1 H, CH), 2.55 (t, J = 7.2 Hz, 2 H, CH2), 1.66
(d, J = 1.2 Hz, 3 H, CH3), 1.58 (d, J = 1.2 Hz, 3 H, CH3), 1.25 (t,
J = 7.1 Hz, 3 H, CH3), 1.24 (t, J = 7.1 Hz, 3 H, CH3), 0.96 (d,
J = 6.8 Hz, 3 H, CH3).
(E)-6-Methylhepta-2,5-dien-1-ol (9i), (2E,5Z)-5-Methylhepta-
2,5-dien-1-ol (10i), 5-Methyl-2-methylenehex-4-en-1-ol (11i),
and (Z)-4-Methyl-2-methylenehex-4-en-1-ol (12i)
Precatalyst: CoBr2(L3). After purification by column chromatogra-
phy (pentane–EtOAc, 10:1), the product (ratio 9i/10i/11i/12i,
8:91:<1:<1; 37 mg, 58%) was obtained as a colourless oil; Rf = 0.21
(pentane–EtOAc, 10:1) (9i/10i).
13C NMR (75 MHz, CDCl3): δ = 169.0 (C=O), 138.4 (Colef), 130.7
(Cq,olef), 128.7 (Colef), 122.8 (Colef), 61.2 (OCH2), 52.3 (CH), 35.4
(CH2), 31.8 (CH), 25.7 (CH3), 21.0 (CH3), 17.8 (CH3), 14.1 (CH3).
MS (EI, 70 eV): m/z (%) = 237 (<1), 191 (2), 179 (2), 161 (2), 147
(7), 135 (3), 122 (46), 107 (100), 93 (14), 79 (14).
HRMS (EI): m/z [M]+ calcd for C16H26O4: 282.1831; found:
282.1813.
IR (film) (9i, 10i): 3351, 3031, 2969, 2927, 2863, 1674, 1443, 1377,
1217, 1085, 995, 971, 823 cm–1.
1H NMR (300 MHz, CDCl3): δ (10i) = 5.77–5.53 (m, 2 H, Holef),
5.35–5.20 (m, 1 H, Holef), 4.09 (s, 2 H, OCH2), 2.82–2.67 (m, 2 H,
CH2), 1.71–1.63 (m, 3 H, CH3), 1.62–1.49 (m, 3 H, CH3).
13C NMR (75 MHz, CDCl3): δ (10i) = 133.7 (Cq,olef), 130.0 (Colef),
129.6 (Colef), 119.9 (Colef), 60.5 (OCH2), 34.4 (CH2), 23.3 (CH3),
13.2 (CH3).
MS (EI, 70 eV): m/z (%) (10i) = 126 (5) [M]+, 111 (4), 108 (18), 98
(34), 93 (63), 82 (46), 79 (40), 70 (42), 67 (100), 55 (93).
HRMS (EI): m/z [M]+ calcd for C8H14O: 126.1045; found:
126.1041.
(E)-4-(4,6-Dimethylhepta-2,5-dienyl)-1,2-dimethoxybenzene
(15c)
After purification by column chromatography (pentane–Et2O, 20:1
→ 10:1), the product (ratio 15c/16c, >99:1; 61 mg, 93%) was ob-
tained as a yellow oil; Rf = 0.13 (pentane–Et2O, 20:1).
IR (neat): 2960, 2926, 2870, 2835, 1592, 1512, 1454, 1419, 1260,
1232, 1140, 1028, 969, 912, 848, 804, 762 cm–1.
1H NMR (300 MHz, CDCl3): δ = 6.84–6.76 (m, 1 H, Har), 6.76–
6.68 (m, 2 H, Har), 5.58–5.39 (m, 2 H, Holef), 5.03–4.95 (m, 1 H,
H
olef), 3.863 (s, 3 H, OCH3), 3.859 (s, 3 H, OCH3), 3.27 (d,
Cobalt-Catalysed 1,4-Hydrovinylation with (E)-2-Methylpen-
ta-1,3-diene (14); General Procedure
J = 5.6 Hz, 2 H, CH2), 3.14–2.98 (m, 1 H, CH), 1.69 (d, J = 1.2 Hz,
3 H, CH3), 1.62 (d, J = 1.2 Hz, 3 H, CH3), 1.04 (d, J = 6.8 Hz, 3 H,
CH3).
13C NMR (75 MHz, CDCl3): δ = 148.8 (Cq,ar), 147.2 (Cq,ar), 136.6
(Colef), 133.7 (Cq), 130.4 (Cq), 129.1 (Colef), 126.5 (Colef), 120.2
(Car), 111.8 (Car), 111.2 (Car), 55.9 (OCH3), 55.7 (OCH3), 38.4
(CH2), 35.3 (CH), 25.7 (CH3), 21.2 (CH3), 17.8 (CH3).
MS (EI, 70 eV): m/z (%) = 260 (37) [M]+, 245 (1), 217 (7), 203 (3),
189 (7), 177 (11), 164 (21), 151 (100), 138 (5), 128 (4), 115 (7), 107
(15), 91 (16), 79 (14).
In a flame-dried Schlenk tube fitted with a Teflon screw cap,
CoBr2(L3) (5–10 mol%), Zn powder (10–20 mol%), and anhyd
ZnI2 (10–20 mol%) were suspended in anhyd CH2Cl2 (0.5 mL) un-
der an argon atmosphere. The terminal alkene (0.25 mmol, 1.0
equiv) was added. A soln of (E)-2–methylpenta-1,3-diene (14, 0.50
mmol, 2.0 equiv) in anhyd CH2Cl2 (0.2 mL) was added dropwise via
syringe over 6 h and the mixture was then stirred at r.t. or 40 °C until
complete conversion of the alkene (monitored by GC/MS, 6–22 h).
The mixture was filtered through a short pad of silica gel (pentane–
Et2O). The solvent was removed under reduced pressure and the
residue was purified by flash column chromatography (silica gel).
The ratios of the regioisomers were determined by GC analysis.
HRMS (EI): m/z [M]+ calcd for C17H24O2: 260.1776; found:
260.1781.
Isobutyl (E)-5,7-Dimethylocta-3,6-dienoate (15a)
(E)-2-(4,6-Dimethylhepta-2,5-dienyl)isoindoline-1,3-dione
(15d)
After purification by column chromatography (pentane–t-BuOMe,
20:1), the product (ratio 15d/16d, >99:1; 78% ee, 66 mg, 98%) was
obtained as a light yellow oil. When the reaction was performed us-
ing ligand (R)-L3, 15d was obtained with 82% ee; Rf = 0.17 (pen-
After purification by column chromatography (pentane–Et2O,
50:1), the product (ratio 15a/16a, >99:1; 43 mg, 78%) was obtained
as a colourless oil; Rf = 0.18 (pentane–Et2O, 50:1).
IR (neat): 2963, 2928, 2874, 1737, 1452, 1375, 1242, 1153, 1001,
968, 835 cm–1.
tane–t-BuOMe, 20:1). RP-HPLC (40–90%
B in 20 min):
1H NMR (300 MHz, CDCl3): δ = 5.56–5.41 (m, 2 H, Holef), 4.99–
4.90 (m, 1 H, Holef), 3.85 (d, J = 6.6 Hz, 2 H, OCH2), 3.13–2.98 (m,
3 H, CH2, CH), 2.00–1.84 (m, 1 H, CH), 1.68 (s, 3 H, CH3), 1.64–
1.58 (m, 3 H, CH3), 1.02 (d, J = 6.8 Hz, 3 H, CH3), 0.92 (d,
J = 6.7 Hz, 6 H, CH3).
13C NMR (75 MHz, CDCl3): δ = 172.2 (C=O), 139.0 (Colef), 130.9
(Cq,olef), 128.5 (Colef), 119.5 (Colef), 70.6 (OCH2), 38.1 (CH2), 35.4
(CH), 27.7 (CH), 25.7 (CH3), 20.9 (CH3), 19.0 (CH3), 17.8 (CH3).
tR = 35.26 (A = 1088.46), 36.17 min (A = 139.77); er 89:11.
IR (neat): 2965, 2923, 2869, 1772, 1709, 1613, 1430, 1389, 1347,
1184, 1065, 964, 844, 756, 717, 618 cm–1.
1H NMR (300 MHz, CDCl3): δ = 7.88–7.79 (m, 2 H, Har), 7.74–
7.66 (m, 2 H, Har), 5.68 (ddt, J = 15.5, 5.9, 1.1 Hz, 1 H, Holef), 5.44
(dtd, J = 15.4, 6.2, 1.4 Hz, 1 H, Holef), 4.95–4.87 (m, 1 H, Holef), 4.22
(d, J = 6.2 Hz, 2 H, CH2), 3.10–2.93 (m, 1 H, CH), 1.66 (d,
J = 0.9 Hz, 3 H, CH3), 1.57 (d, J = 1.1 Hz, 3 H, CH3), 0.99 (d,
J = 6.9 Hz, 3 H, CH3).
MS (EI, 70 eV): m/z (%) = 224 (20) [M]+, 209 (6), 167 (13), 153
(55), 135 (13), 121 (46), 107 (100), 93 (47), 81 (31), 67 (15).
Synthesis 2012, 44, 3534–3542
© Georg Thieme Verlag Stuttgart · New York

PAPER
Ligand-Controlled Cobalt-Catalysed 1,4-Hydrovinylation Reaction
3541
13C NMR (75 MHz, CDCl3): δ = 168.0 (C=O), 139.6 (Colef), 133.8
(Car), 132.2 (Cq), 131.1 (Cq), 128.1 (Colef), 123.2 (Car), 120.8 (Colef),
39.6 (CH2), 34.9 (CH), 25.7 (CH3), 20.7 (CH3), 17.8 (CH3).
13C NMR (75 MHz, CDCl3): δ (15g) = 170.8 (C=O), 140.6 (Colef),
131.3 (Cq,olef), 128.0 (Colef), 121.5 (Colef), 65.3 (OCH2), 35.1 (CH),
25.7 (CH3), 21.0 (CH3), 20.7, (CH3), 17.8 (CH3).
MS (EI, 70 eV): m/z (%) = 269 (3) [M]+, 226 (2), 214 (1), 198 (1),
186 (5), 160 (31), 148 (10), 130 (16), 122 (46), 107 (100), 91 (21),
77 (26).
MS (EI, 70 eV): m/z (%) (15g) = 167 (<1), 153 (<1), 140 (1), 126
(1), 122 (21), 107 (100), 97 (5), 91 (22), 83 (6), 79 (19), 67 (11).
HRMS (ESI): m/z [M + Na]+ calcd for C11H18O2Na: 205.1199;
found: 205.1198.
HRMS (EI): m/z [M]+ calcd for C17H19NO2: 269.1416; found:
269.1415.
(E)-[(4,6-Dimethylhepta-2,5-dienyloxy)methyl]benzene (15h)
and {[(2E,5Z)-5-Methylocta-2,5-dienyloxy]methyl}benzene
(16h)
After purification by column chromatography (pentane–Et2O,
50:1), the product (ratio 15h/16h, 96:4; 19 mg, 32%) was obtained
as a colourless oil; Rf = 0.22 (pentane–Et2O, 50:1).
(E)-7,9-Dimethyldeca-5,8-dien-2-one (15e)
After purification by column chromatography (pentane–t-BuOMe,
20:1), the product (ratio 15e/16e, >99:1; 24 mg, 53%) was obtained
as a light yellow oil; Rf = 0.27 (pentane–t-BuOMe, 20:1).
IR (neat): 2963, 2922, 2868, 1715, 1445, 1361, 1225, 1160, 1049,
969, 840, 740 cm–1.
IR (neat): 3030, 2965, 2926, 2854, 1496, 1452, 1360, 1203, 1099,
1070, 1028, 970, 841, 734, 696, 604 cm–1.
1H NMR (300 MHz, CDCl3): δ = 5.44–5.25 (m, 2 H, Holef), 4.97–
4.88 (m, 1 H, Holef), 3.05–2.89 (m, 1 H, CH), 2.47 (t, J = 7.4 Hz, 2
H, CH2), 2.29–2.19 (m, 2 H, CH2), 2.12 (s, 3 H, CH3), 1.67 (d,
J = 1.2 Hz, 3 H, CH3), 1.59 (d, J = 1.2 Hz, 3 H, CH3), 0.98 (d,
J = 6.8 Hz, 3 H, CH3).
13C NMR (75 MHz, CDCl3): δ = 208.5 (C=O), 136.1 (Colef), 130.5
(Cq,olef), 129.0 (Colef), 125.8 (Colef), 43.6 (CH2), 35.3 (Caliph), 29.9
(Caliph), 26.8 (Caliph), 25.7 (CH3), 21.2 (CH3), 17.8 (CH3).
MS (EI, 70 eV): m/z (%) = 180 (<1) [M]+, 147 (2), 137 (1), 122 (38),
107 (100), 91 (16), 79 (16), 67 (12).
HRMS (EI): m/z [M]+ calcd for C12H20O: 180.1514; found:
180.1518.
1H NMR (300 MHz, CDCl3): δ (15h) = 7.40–7.24 (m, 5 H, Har),
5.66 (dd, J = 15.5, 5.8 Hz, 1 H, Holef), 5.54 (dtd, J = 15.5, 5.9,
0.9 Hz, 1 H, Holef), 5.02–4.92 (m, 1 H, Holef), 4.50 (s, 2 H, CH2), 3.98
(d, J = 5.9 Hz, 2 H, CH2), 3.16–3.00 (m, 1 H, CH), 1.70 (d, J = 0.9
Hz, 3 H, CH3), 1.63 (d, J = 1.1 Hz, 3 H, CH3), 1.05 (d, J = 6.9 Hz,
3 H, CH3).
13C NMR (75 MHz, CDCl3): δ (15h) = 139.2 (Colef), 138.5 (Cq,ar),
130.9 (Cq,olef), 128.5 (Colef), 128.3 (Car), 127.8 (Car), 127.5 (Car),
123.9 (Colef), 71.9 (CH2), 71.0 (CH2), 35.1 (CH), 25.7 (CH3), 20.8
(CH3), 17.9 (CH3).
MS (EI, 70 eV): m/z (%) (15h) = 230 (<1) [M]+, 215 (<1), 186 (1),
174 (4), 145 (1), 139 (4), 122 (11), 107 (15), 91 (100), 83 (8), 77
(11).
HRMS (EI): m/z [M]+ calcd for C16H22O: 230.1671; found:
230.1672.
(E)-2-(4,6-Dimethylhepta-2,5-dienyl)cyclohexanone (15f)
After purification by column chromatography (pentane–t-BuOMe,
40:1), the product (ratio 15f/16f, >99:1; 25 mg, 45%) was obtained
as a colourless oil; Rf = 0.22 (pentane–t-BuOMe, 40:1).
(E)-(4,6-Dimethylhepta-2,5-dienyloxy)benzene (15i)
IR (neat): 2961, 2928, 2862, 1710, 1666, 1448, 1377, 1312, 1128,
1061, 970, 838, 725 cm–1.
1H NMR (600 MHz, CDCl3): δ = 5.35 (dd, J = 15.4, 5.9 Hz, 1 H,
After purification by column chromatography (pentane–EtOAc,
80:1), the product (ratio 15i/16i, >99:1; 34 mg, 63%) was obtained
as a colourless oil; Rf = 0.18 (pentane–EtOAc, 80:1).
H
olef), 5.33–5.27 (m, 1 H, Holef), 4.96–4.91 (m, 1 H, Holef), 3.02–2.94
IR (neat): 3031, 2965, 2923, 2867, 1596, 1494, 1454, 1378, 1297,
1237, 1171, 1013, 970, 837, 751, 690 cm–1.
(m, 1 H, CH), 2.49–2.42 (m, 1 H, Haliph), 2.38 (dt, J = 8.3, 3.3 Hz, 1
H, Haliph), 2.32–2.24 (m, 2 H, Haliph), 2.13–2.06 (m, 1 H, Haliph),
2.06–2.00 (m, 1 H, Haliph), 1.94–1.86 (m, 1 H, Haliph), 1.86–1.81 (m,
1 H, Haliph), 1.70–1.61 (m, 2 H, Haliph), 1.68 (d, J = 1.0 Hz, 3 H,
CH3), 1.60 (s, 3 H, CH3), 1.38–1.29 (m, 1 H, Haliph), 0.98 (d,
J = 6.9 Hz, 3 H, CH3).
13C NMR (150 MHz, CDCl3): δ = 212.8 (C=O), 137.1, 137.0 (Colef),
130.3 (Cq,olef), 129.1 (Colef), 125.09, 125.07 (Colef), 50.81, 50.79
(CH), 42.0 (CH2), 35.41, 35.38 (CH), 33.2 (CH2), 32.5, 32.4 (CH2),
27.9 (CH2), 25.7 (CH3), 24.9 (CH2), 21.3 (CH3), 17.8 (CH3).
MS (EI, 70 eV): m/z (%) = 220 (<1) [M]+, 187 (1), 163 (1), 149 (1),
135 (4), 122 (39), 107 (100), 91 (13), 79 (14), 67 (12).
HRMS (EI): m/z [M]+ calcd for C15H24O: 220.1827; found:
220.1828.
1H NMR (300 MHz, CDCl3): δ = 7.25–7.15 (m, 2 H, Har), 6.90–
6.80 (m, 3 H, Har), 5.70 (ddt, J = 15.5, 5.9, 0.9 Hz, 1 H, Holef), 5.58
(dtd, J = 15.5, 5.7, 1.0 Hz, 1 H, Holef), 4.95–4.86 (m, 1 H, Holef), 4.39
(dt, J = 5.7, 0.9 Hz, 2 H, CH2), 3.11–2.95 (m, 1 H, CH), 1.63 (d,
J = 1.2 Hz, 3 H, CH3), 1.55 (d, J = 1.3 Hz, 3 H, CH3), 0.99 (d,
J = 6.8 Hz, 3 H, CH3).
13C NMR (75 MHz, CDCl3): δ = 158.8 (Cq,ar), 139.6 (Colef), 131.2
(Cq,olef), 129.4 (Car), 128.2 (Colef), 122.6 (Colef), 120.6 (Car), 114.8
(Car), 68.8 (CH2), 35.2 (CH), 25.7 (CH3), 20.7 (CH3), 17.9 (CH3).
MS (EI, 70 eV): m/z (%) = 216 (1) [M]+, 160 (1), 133 (4), 123 (89),
107 (13), 93 (23), 81 (100), 65 (41), 55 (23).
HRMS (EI): m/z [M]+ calcd for C15H20O: 216.1514; found:
216.1515.
(E)-4,6-Dimethylhepta-2,5-dienyl Acetate (15g) and (2E,5Z)-5-
Methylocta-2,5-dienyl Acetate (16g)
After purification by column chromatography (pentane–Et2O,
30:1), the product (ratio 15g/16g, 96:4; 45 mg, 99%) was obtained
as a colourless oil; Rf = 0.22 (pentane–Et2O, 30:1).
(E)-4,6-Dimethylhepta-2,5-dien-1-ol (15j) and (2E,5Z)-5-Meth-
ylocta-2,5-dien-1-ol (16j)
After purification by column chromatography (pentane–EtOAc,
10:1), the product (ratio 15j/16j, 91:9; 34 mg, 97%) was obtained as
a colourless oil; Rf = 0.26 (pentane–EtOAc, 10:1).
IR (neat): 2965, 2927, 2871, 1739, 1448, 1373, 1227, 1085, 1023,
965, 836, 607 cm–1.
IR (neat): 2965, 2926, 2868, 1450, 1377, 1090, 1006, 969, 840, 544
cm–1.
1H NMR (300 MHz, CDCl3): δ (15j) = 5.69–5.50 (m, 2 H, Holef),
5.00–4.89 (m, 1 H, Holef), 4.11–4.03 (m, 2 H, CH2), 3.15–2.97 (m, 1
H, CH), 1.69 (d, J = 1.1 Hz, 3 H, CH3), 1.62 (d, J = 1.2 Hz, 3 H,
CH3), 1.38 (br s, 1 H, OH), 1.03 (d, J = 6.8 Hz, 3 H, CH3).
1H NMR (300 MHz, CDCl3): δ (15g) = 5.69 (ddt, J = 15.5, 6.0,
1.0 Hz, 1 H, Holef), 5.50 (dtd, J = 15.4, 6.4, 1.3 Hz, 1 H, Holef), 4.99–
4.90 (m, 1 H, Holef), 4.51 (d, J = 6.4 Hz, 2 H, OCH2), 3.15–2.99 (m,
1 H, CH), 2.06 (s, 3 H, CH3), 1.69 (d, J = 1.2 Hz, 3 H, CH3), 1.61
(d, J = 1.2 Hz, 3 H, CH3), 1.04 (d, J = 6.8 Hz, 3 H, CH3).
© Georg Thieme Verlag Stuttgart · New York
Synthesis 2012, 44, 3534–3542

3542
M. Arndt et al.
PAPER
13C NMR (75 MHz, CDCl3): δ (15j) = 137.7 (Colef), 131.0 (Cq,olef),
128.4 (Colef), 126.5 (Colef), 63.8 (CH2), 35.1 (CH), 25.7 (CH3), 20.9
(CH3), 17.8 (CH3).
MS (EI, 70 eV): m/z (%) (15j) = 140 (1) [M]+, 122 (25), 109 (100),
105 (23), 96 (36), 91 (63), 83 (38), 79 (64), 67 (73), 55 (98).
HRMS (ESI): m/z [M + Na]+ calcd for C9H16ONa: 163.1093; found:
163.1093.
Organometallics 2005, 24, 5499. For 1,2-hydrovinylations
catalysed by Ru, see: (x) Jiang, G.; List, B. Chem. Commun.
2011, 47, 10022. (y) Gavenonis, J.; Arroyo, R. V.; Snapper,
M. L. Chem. Commun. 2010, 46, 5692. (z) Sanchez, R. P. Jr;
Connell, B. T. Organometallics 2008, 27, 2902. (aa) Kondo,
T.; Takagi, D.; Tsujita, H.; Ura, Y.; Wada, K.; Mitsudo, T.-
a. Angew. Chem. Int. Ed. 2007, 46, 5958. For Fe-catalysed
hydrovinylations, see: (ab) Russell, S. K.; Lobkovsky, E.;
Chirik, P. J. J. Am. Chem. Soc. 2011, 133, 8858. (ac) Small,
B. L.; Marcucci, A. J. Organometallics 2001, 20, 5738.
(2) For recent general reviews on Co-catalysed reactions, see:
(a) Hilt, G. Eur. J. Org. Chem. 2012, 4441. (b) RajanBabu,
T. V. Chem. Rev. 2003, 103, 2845. (c) RajanBabu, T. V.
Synlett 2009, 853. For Co-catalysed 1,4-hydrovinylations,
see: (d) Kersten, L.; Hilt, G. Adv. Synth. Catal. 2012, 354,
863. (e) Erver, F.; Hilt, G. Org. Lett. 2011, 13, 5700.
(f) Arndt, M.; Reinhold, A.; Hilt, G. J. Org. Chem. 2010, 75,
5203. (g) Kersten, L.; Roesner, S.; Hilt, G. Org. Lett. 2010,
12, 4920. (h) Hilt, G.; Arndt, M.; Weske, D. F. Synthesis
2010, 1321. (i) Hilt, G.; Treutwein, J. Chem. Commun. 2009,
1395. (j) Hilt, G.; Danz, M.; Treutwein, J. Org. Lett. 2009,
11, 3322. (k) Hilt, G.; Lüers, S.; Schmidt, F. Synthesis 2004,
634.
Acknowledgement
We thank German Science foundation for financial support. We
thank Marianne Wenzel and Prof. Eric Meggers for the enantiome-
ric excess measurements by chiral RP-HPLC.
References
(1) For reviews, see: (a) Hess, W.; Treutwein, J.; Hilt, G.
Synthesis 2008, 3537. (b) Omae, I. Appl. Organomet. Chem.
2007, 21, 318. (c) Jeganmohan, M.; Cheng, C.-H. Chem.–
Eur. J. 2008, 14, 10876. (d) Laschat, S.; Becheanu, A.; Bell,
T.; Baro, A. Synlett 2005, 2547. For 1,2-hydrovinylations
catalysed by Ni, see: (e) Ho, C.-Y.; He, L. Angew. Chem. Int.
Ed. 2010, 49, 9182. (f) Zhang, Q.; Zhu, S.-F.; Cai, Y.; Wang,
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(g) Lassauque, N.; Franciò, G.; Leitner, W. Adv. Synth.
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(k) Lassauque, N.; Franciò, G.; Leitner, W. Eur. J. Org.
Chem. 2009, 3199. (l) Joseph, J.; RajanBabu, T. V.; Jemmis,
E. D. Organometallics 2009, 28, 3552. (m) Smith, C. R.;
RajanBabu, T. V. J. Org. Chem. 2009, 74, 3066. (n) Saha,
B.; Smith, C. R.; RajanBabu, T. V. J. Am. Chem. Soc. 2008,
130, 9000. (o) Zhang, Q.; Zhu, S.-F.; Qiao, X.-C.; Wang, L.-
X.; Zhou, Q.-L. Adv. Synth. Catal. 2008, 350, 1507. For 1,2-
hydrovinylations catalysed by Pd, see: (p) Ayora, I.; Ceder,
R. M.; Espinel, M.; Muller, G.; Rocamora, M.; Serrano, M.
Organometallics 2011, 30, 115. (q) Rodríguez, L.-I.;
Rossell, O.; Seco, M.; Orejón, A.; Masdeu-Bultó, A. M. J.
Organomet. Chem. 2008, 693, 1857. For 1,2-
(3) Hilt, G.; Roesner, S. Synthesis 2011, 662.
(4) SchmalzPhos = (3aR,8aR)-6-[3-(diphenylphosphino)bi-
phenyl-2-yloxy]-2,2-dimethyl-4,4,8,8-tetraphenyltetra-
hydro[1,3]dioxolo[4,5-e][1,3,2]dioxaphosphepine. For
synthetic applications, see also: (a) Kranich, R.; Eis, K.;
Geis, O.; Mühle, S.; Bats, J. W.; Schmalz, H.-G. Chem.–Eur.
J. 2000, 6, 2874. (b) Blume, F.; Zemolka, S.; Fey, T.;
Kranich, R.; Schmalz, H.-G. Adv. Synth. Catal. 2002, 344,
868. (c) Robert, T.; Velder, J.; Schmalz, H.-G. Angew.
Chem. Int. Ed. 2008, 47, 7718. (d) Lölsberg, W.; Ye, S.;
Schmalz, H.-G. Adv. Synth. Catal. 2010, 352, 2023.
(e) Robert, T.; Abiri, Z.; Wassenaar, J.; Sande, A. J.;
Romanski, S.; Neudörfl, J.-M.; Schmalz, H.-G.; Reek, J. N.
H. Organometallics 2010, 29, 478. (f) Robert, T.; Abiri, Z.;
Sandee, A. J.; Schmalz, H.-G.; Reek, J. N. H. Tetrahedron:
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Hilt, G.; Dindaroğlu, M.; Schmalz, H.-G. Angew. Chem. Int.
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(5) Arndt, M.; Dindaroğlu, M.; Schmalz, H.-G.; Hilt, G. Org.
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(6) For the synthesis of the ligands L1 and L3, see: Velder, J.;
Robert, T.; Weidner, I.; Neudörfl, J.-M.; Lex, J.; Schmalz,
H.-G. Adv. Synth. Catal. 2008, 350, 1309.
(7) Moreau, B.; Wu, J. Y.; Ritter, T. Org. Lett. 2009, 11, 337.
(8) (a) Starting material 14 was obtained from 2-methylpentane-
2,4-diol as a mixture with 4-methylpenta-1,3-diene,
following the procedure reported by: Williams, P. H.; Finch,
H. V. de; Ballard, S. A. (Shell Development Company) GB
572602 1945. (b) The side product 4-methylpenta-1,3-diene
is unreactive under the reaction conditions and remains
unchanged.
hydrovinylations catalysed by Co, see: (r) Grutters, M. M.
P.; van der Vlugt, J. I.; Pei, Y.; Mills, A. M.; Lutz, M.; Spek,
A. L.; Müller, C.; Moberg, C.; Vogt, D. Adv. Synth. Catal.
2009, 351, 2199. (s) Grutters, M. M. P.; Müller, C.; Vogt, D.
J. Am. Chem. Soc. 2006, 128, 7414. For 1,2-
hydrovinylations catalysed by Pt, see: (t) Serra, D.; Cao, P.;
Cabrera, J.; Padilla, R.; Rominger, F.; Limbach, M.
Organometallics 2011, 30, 1885. (u) Cucciolito, M. E.;
D’Amora, A.; Vitagliano, A. Organometallics 2005, 24,
3359. For 1,2-hydrovinylations catalysed by Ir, see:
(v) Oxgaard, J.; Bhalla, G.; Periana, R. A.; Goddard, W. A.
III Organometallics 2006, 25, 1618. (w) Bhalla, G.;
Oxgaard, J.; Goddard, W. A. III; Periana, R. A.
(9) Hilt, G.; Hess, W.; Harms, K. Org. Lett. 2006, 8, 3287.
(10) Hong, A.; Friedman, J. M. Synth. Commun. 1997, 27, 2971.
Synthesis 2012, 44, 3534–3542
© Georg Thieme Verlag Stuttgart · New York