The utility of vinyl ethers and vinyl esters in the Khand reaction. The value of vinyl esters as ethylene equivalents and a modified synthesis of (+)-taylorione as an example

Article abstract of DOI:10.1016/S0022-328X(01)00891-9

The behaviour of various oxygenated alkenes in the Khand cyclisation reaction has been studied. Although several vinyl ethers reacted to give the expected oxygenated cyclopentenone products, usually with good levels of regioselectivity, the use of vinyl esters was found to afford, as the major products, reduced cyclopentenones in which the carbon-oxygen bond had been cleaved. This unexpected reaction was developed into an alternative procedure to using ethylene gas in the Khand reaction and was found to be applicable with a variety of alkyne substrates. The method was then extended to form the key step in the synthesis of the natural product (+)-taylorione (and (+)-nortaylorione).

Full text of DOI:10.1016/S0022-328X(01)00891-9

Journal of Organometallic Chemistry 630 (2001) 104–117
www.elsevier.com/locate/jorganchem
The utility of vinyl ethers and vinyl esters in the Khand reaction.
The value of vinyl esters as ethylene equivalents and a modified
synthesis of (+)-taylorione as an example
William J. Kerr *, Mark McLaughlin, Peter L. Pauson, Sarah M. Robertson
Department of Pure and Applied Chemistry, Uni6ersity of Strathclyde, Thomas Graham Building, Glasgow G1 1XL, Scotland, UK
Received 18 January 2001; received in revised form 27 March 2001; accepted 27 March 2001
We dedicate this and the following paper to Myron Rosenblum on the occasion of his 75th birthday in friendship and admiration of his
elegant contributions to organo-transition metal chemistry
Abstract
The behaviour of various oxygenated alkenes in the Khand cyclisation reaction has been studied. Although several vinyl ethers
reacted to give the expected oxygenated cyclopentenone products, usually with good levels of regioselectivity, the use of vinyl
esters was found to afford, as the major products, reduced cyclopentenones in which the carbon–oxygen bond had been cleaved.
This unexpected reaction was developed into an alternative procedure to using ethylene gas in the Khand reaction and was found
to be applicable with a variety of alkyne substrates. The method was then extended to form the key step in the synthesis of the
natural product (+)-taylorione (and (+)-nortaylorione). © 2001 Elsevier Science B.V. All rights reserved.
Keywords: Khand reaction; Vinyl ethers; Vinyl esters; Ethylene equivalent; Taylorione; Nortaylorione
1. Introduction
under very mild reaction conditions, however, the be-
haviour of vinyl esters is more complex than initially
suspected. As previously reported in preliminary form
[3], under most conditions tried, the expected formation
of 4- and 5-acyloxycyclopentenones is accompanied or
replaced by reductive loss of the ester group. Similar
cleavage had accompanied the reactions of vinyl bro-
mide [4] so that both this and the vinyl esters can serve
as substitutes for ethylene. As we were able to obtain
moderate yields by these procedures, the greater conve-
nience of using liquid alkenes in place of ethylene,
which requires autoclave conditions for best results
[5,6], prompted us to study the optimum choice of
reactants and conditions.
Our results are outlined below, together with at-
tempts to apply the new vinyl ester–ethylene equivalent
method as an alternative procedure in the previously
described synthesis of the natural product, taylorione
[6] (and the preparation of the related natural material,
(+)-nortaylorione).
Croudace and Schore first used vinyl ethers and
esters in the Khand reaction in l981 [1]. Despite the fact
that they obtained mixtures of regioisomers in rather
low yields, we were interested in utilising such reactions
towards the synthesis of natural products and specifi-
cally of the pentenomycins. Initially we failed to isolate
the 4-alkoxycyclopentenones from reactions of vinyl
ethers [2], but we suspected that the greater ease of
elimination of alcohols from these compounds com-
pared to the 5-isomers might be responsible. Having
now repeated the reactions under considerably milder
reaction conditions, we conclude that 5-alkoxycy-
clopent-2-en-1-ones are always the major products and
that the 4-isomers are only isolable in some cases. Even
* Corresponding author. Tel.: +44-141-5482959; fax: +44-141-
5484246.
E-mail address: cbas69@strath.ac.uk (W.J. Kerr).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00891-9

W.J. Kerr et al. / Journal of Organometallic Chemistry 630 (2001) 104–117
105
product 1c with ethyl vinyl ether. The yield reached an
optimum of 35% when TMANO·2H2O was employed
with sonication in a solvent mixture of methanol and
toluene.
Use of 2,3-dihydrofuran as the alkene led to a single
isomer 3 with each of the alkyne complexes tried;
isomer 4 was not detected (Scheme 2). More specifi-
cally, with the ethyne complex under promotion by
NMO·H2O, a 48% yield of the bicyclic product 3a was
obtained. Similar procedures with the phenylethyne
complex gave an optimum yield of 52% for compound
3b. Furthermore, ketone 3c was isolated in 49% yield
from reaction of the corresponding dimethylpropargyl
alcohol complex in toluene–methanol using the alkene
as co-solvent, TMANO·2H2O as promoter, and sonica-
tion for 30 min.
From these results it can be seen that, by the applica-
tion of more recently developed milder and more effi-
cient Khand reaction promotion methods, oxygenated
cyclopentenone products from reactions of enol ethers
can be obtained in moderate to good yields and with, at
least, good levels of regioselectivity; in most instances,
only one regioisomer is isolated.
Scheme 1. Khand reaction of alkynehexacarbonyldicobalt complexes
with ethyl vinyl ether.
2. Results and discussion
The introduction of amine N-oxides to promote
Khand annulation reactions has allowed the use of very
mild reaction conditions and has frequently led to
substantially enhanced yields [5–8]. At the outset, it
seemed worthwhile to determine whether these or other
improved reaction conditions would also lead to signifi-
cantly greater yields of alkoxy- and, in turn, hydroxycy-
clopentenones when applied to previously studied
examples of vinyl ethers and esters [1,2].
2.1. Reactions of 6inyl ethers
The reactions of ethyl vinyl ether with, in particular,
the hexacarbonyldicobalt complexes of ethyne and of
phenylethyne were examined under various conditions
in an attempt to maximise the formation of the ethoxy-
cyclopentenones 1 and 2 (Scheme 1). Simple thermal
reaction of the ethyne complex in toluene at 65 °C had
given only low yields of 5-ethoxycyclopent-2-en-1-one
(1a). Its isomer 2a was not detected. Under the milder
conditions available with N-oxide or sulfide promotion
[9] improved efficiency was observed; a 32% yield of 1a
was reached using either n-butyl methyl sulfide or the
recently reported combination of ultrasound and
trimethylamine N-oxide dihydrate (TMANO·2H2O)
[10]. Compound 2a was again not detected.
With the phenylethyne complex the 4-substituted cy-
clopentenone was also isolated. Under thermal condi-
tions (toluene, 70 °C) a 20% yield of ethoxyketones 1b
and 2b (ca. 7:2) was obtained. Using anhydrous N-
methylmorpholine N-oxide (NMO) with ultrasound the
yield of this mixture rose to 31%. With NMO·H2O in
dichloromethane and excess ethyl vinyl ether as co-sol-
vent, a 43% yield of only isomer 1b was produced.
In similar fashion to ethyne, the hexacarbonyldi-
cobalt complex of 2-methylbut-3-yn-2-ol gave only the
2.2. Reactions of 6inyl esters and halides
We next investigated the behaviour of vinyl acetate
within the Khand annulation process. Early results
seemed similar to those with ethyl vinyl ether: without
promoter reactions required prolonged heating and
gave poor yields of one isomer 5 only [2]. However,
when the phenylethyne complex was treated with vinyl
acetate using amine N-oxide promoted conditions, the
situation was seen to be more complex. With
TMANO·2H2O in methanol and an excess of vinyl
acetate as co-solvent in toluene at 45 °C or again with
the same N-oxide promoter with sonication (35 min)
the product, obtained in 53 and 51% yield, respectively,
was 2-phenylcyclopent-2-en-1-one (7) (entries 1 and 2,
Table 1). None of the expected acetoxy-substituted
products 5b and 6b were observed. This behaviour was
reminiscent of the formation of the same product, albeit
in only 19% yield, noted previously by Khand [4] when
using vinyl bromide as the alkene. Indeed, this yield
could also be raised to 54% when vinyl bromide was
used with NMO·H2O (entry 3, Table 1).
These results suggested that vinyl esters or halides
could find general use to replace ethylene in the Khand
reaction and avoid the need to employ autoclaves for
Scheme 2. Khand reaction of alkynehexacarbonyldicobalt complexes
with 2,3-dihydrofuran.

Table 1
/
Khand reactions of (PhCꢀCH)Co2(CO)6 with vinyl esters and vinyl bromide
a
Entry
Complex
(mg)
Vinyl-X
Amine N-oxide
Solvent
Type
Conditions
Yield
(mg)
(mmol)
Type
(g)
(mmol)
Addition time
(ml)
Temp. (°C)
Time
(%)
1
2
3
4
5
6
7
150
190
540
560
350
670
380
0.39
0.49
1.39
1.44
0.90
1.73
0.98
X=OAc, 4 ml
X=OAc, 4 ml
X=Br, 14 ml b
X=OPiv, 1.8 g
X=OCOCF3, 1.3 g
X=OBz, 2.6 g
X=OBz, 3.0 g
TMANO·2H2O
TMANO·2H2O
NMO·H2O
NMO·H2O
NMO·H2O
0.39
0.49
1.63
1.69
1.00
2.00
1.32
3.51
4.41
12.07
12.52
7.41
30 s
30 s
Tol., MeOH
Tol., MeOH
DCM
DCM
DCM
10.5, 1
12, 1.5
20
20
20
45
)))
25
25
25
25
25
1 h
30
40
120
70
70
160
120
53
51
54
31
50
58
80
35 min
16 h
16 h
48 h
16 h
16 h
10 min
10 min
10 min
10 min
3 h
NMO·H2O
NMO·H2O
14.81
9.78
DCM
DCM
30
30
630
a The symbol ))) refers to ultrasonication conditions.
b 1 M solution in THF.
(
104
1

W.J. Kerr et al. / Journal of Organometallic Chemistry 630 (2001) 104–117
107
Scheme 3. Khand reaction of phenylethynehexacarbonyldicobalt with
vinyl esters and vinyl bromide.
Scheme 4. Khand reaction of alkynehexacarbonyldicobalt complexes
with vinyl benzoate.
optimum yields [5,6]. Systematic variation of the choice
of vinyl ester and reaction conditions showed that the
yield of 2-phenylcyclopent-2-en-1-one (7), could be
raised up to 80% by employing vinyl benzoate as the
alkene and co-solvent and adding the promoter,
NMO·H2O, slowly by means of a syringe pump
(Scheme 3, Table 1). The full range of modified condi-
tions and results is collected in the tables contained
within supplementary material that may be requested
from the corresponding author.
Having selected vinyl benzoate as the alkene of
choice, we compared its use with a series of alkyne
complexes 8, some of which had been previously stud-
ied with ethylene. The results, as summarised in Table
2, show that the majority of alkynes tested gave fair to
excellent yields of the corresponding cyclopentenones 9
(and 7) (Scheme 4). Indeed, in the cases where a
comparison can be made, the vinyl benzoate technique
provides yields that are, in almost every instance,
greater than those achievable by using the practically
less convenient optimum conditions with ethylene gas
[5,6a]. It is worth noting that although the complex of
propargyl alcohol gave only a 33% yield, to our knowl-
edge, the Khand reaction with the same complex and
ethylene gas has not been achieved. Furthermore, since
the THP-protected form of this alkyne gave an 87%
yield of the corresponding cyclopentenone 9b, simple
deprotection allows access to the free alcohol 9e. In-
deed, such deprotection of 9b and of the homologous
cyclopentenone 9c gave the corresponding free hydroxy
cyclopent-2-en-1-ones 9e and 9f in 99 and 95% yield,
respectively. Internal alkynes are known to react less
efficiently in intermolecular Khand cyclisations [11] and
in the one example attempted with the new ethylene
equivalent technique this is still the case. More specifi-
cally, when the hexacarbonyldicobalt complex of 2-bu-
tyne was subjected to the optimum developed
conditions with vinyl benzoate, the expected 2,3-
dimethylcyclopent-2-en-1-one was formed in only 5%
yield.
With respect to the mode of reaction incorporating
loss of the ester unit, it was further noted that, with the
phenylethyne complex and vinyl acetate, the reductive
cleavage of the alkene moiety, leading to ketone 7, only
occurred under an inert atmosphere, whereas reaction
in air gave only the 5-acetoxyketone 5b, albeit in poor
7% yield. When anhydrous NMO and dry reactants
were employed with the same complex and vinyl ace-
tate, the same product 5b (admixed with the 4-ace-
toxyketone 6b) formed in a combined yield of 4%
(along with a 30% yield of ketone 7). This indicates that
the source of the hydrogen atom introduced in the
cleavage process is water. In confirmation, we were able
to form 5-deuterio-2-phenylcyclopent-2-en-1-one, in a
good 62% yield, by using anhydrous NMO as pro-
moter, with the phenylethyne complex and vinyl ben-
zoate, and adding D2O to the reaction mixture. If we
accept that the mechanism of the Khand reaction in-
volves complexation of alkene to cobalt followed by
insertion into a cobalt to acetylene–carbon bond [11d],
the latter insertion step must precede the CꢁO bond
scission to account for the regioselective formation of
the 5- (and not the 4-) deuterio compound. Further-
more, the CꢁO cleavage and subsequent replacement of
the ester oxygen with H must involve a low oxidation
Table 2
Khand reactions of alkynehexacarbonyldicobalt complexes with vinyl benzoate
Entry
Complex
Product
Yield (%)
Literature yield with ethylene [5,6a]
Ambient conditions a
Autoclave conditions b
1
2
3
4
5
6
7
PhꢁCꢀCꢁH
7
80
77
87
80
45
33
61
52
58
33
–
35
–
71
73
22
–
48
–
8a
8b
8c
8d
8e
8f
9a
9b
9c
9d
9e
9f
–
–
a 1 atm, 25 °C.
b 25–30 atm, 40 °C.

108
W.J. Kerr et al. / Journal of Organometallic Chemistry 630 (2001) 104–117
this regard, we chose one of the best and carefully
optimised cases for which we had previously used ethyl-
ene: the conversion of the hexacarbonyl(alkyne)dicobalt
complex 10 to the cyclopentenone 11, a key step in the
synthesis of (+)-taylorione 12. This Khand reaction
had been accomplished in 81% yield using ethylene
under 25 atm. pressure at 40 °C with TMANO·2H2O
as the reaction promoter [6]. Alternatively, bubbling the
gas through a benzene solution of the complex while
slowly adding TMANO·2H2O in methanol at room
temperature had afforded a still acceptable 41% yield of
11 [6]. In a further modification of this synthesis the
free alkyne required to obtain complex 10 was prepared
in a single step from the corresponding aldehyde using
the procedure of Ohira and Bestmann [12] and in an
enhanced yield (85%) over the previously employed [6]
two-step Ramirez–Corey method [13].
As can be seen from Scheme 6, in the key Khand
annulation, when vinyl benzoate replaced ethylene in
the reaction with complex 10, the ketone 11 was ob-
tained in 60% yield. Thus, whereas this method fails to
match the result obtainable with ethylene under pres-
sure, it is a significant advance on the use of the gas
under ambient conditions. Additionally, the ethylene
equivalent process shows how cheap, readily available,
and easily handled vinyl esters can be employed under
ambient conditions, and thus can be recommended for
use without the requirement of suitable pressure vessels
or a source of ethylene under pressure.
state cobalt species, as anticipated under the reaction
conditions. Additionally, it seems likely that water
causes partial disproportionation of the cobalt(0) pre-
cursor to yield HCo(CO)4, which could also become the
effective reducing agent. Scheme 5 depicts our tentative
mechanistic reasoning for the formation of the reduced
cyclopentenones following regioselective cyclisation
with the vinyl ester; the phenylethyne complex, vinyl
benzoate, and D2O are used to illustrate the outcome of
the labelling process as described above. The initially
produced substituted cyclopentenone will be reduced to
give the corresponding ketyl. Elimination of the ben-
zoate unit, further reduction to the enolate, and subse-
quent quenching with D2O will deliver the reduced
(and, in this case, labelled) cyclopentenone.
2.3. Synthesis of (+)-taylorione (and
(+)-nortaylorione)
Having established efficient and practically conve-
nient conditions for the use of vinyl benzoate in place
of ethylene, we wished to show the utility of this
method when applied to a more complex example. In
With respect to the Khand cyclisation reaction to
form 11 (Scheme 6), it is also worth noting that this
annulation provides the ketal protected form of the
recently reported (+)-nortaylorione 13 [14]. Since we
have prepared this natural product from 11 [6], by our
novel PPh3–CBr4 ketal deprotection method [15], the
strategy reported here also constitutes a formal total
synthesis of (+)-nortaylorione 13.
Scheme 5. Tentative mechanistic reasoning for formation of reduced
cyclopentenones.
2.4. Miscellaneous aspects
Another vinyl ester tested under the developed
Khand techniques was the sulfur-containing compound
BuSCH2COOCHꢂCH2 (14). This was chosen since
Krafft had shown that sulfur in the bis-homoallylic
position (as well as the in the allylic and homoallylic
positions) could, by coordination to cobalt, improve
regioselectivity and yields in Khand processes [16].
From our result with the phenylethyne complex, it
seems that such coordination, if it occurs in the present
case, does not cause this vinyl ester to behave differ-
ently from other vinyl esters and leads to a 60% yield of
the reduced cyclopentenone 7 (Scheme 7).
We also wished to ascertain whether the reductive
elimination of an ester group would occur in an in-
tramolecular Khand reaction. To this end ester 15 (as
an E/Z mixture) was prepared from diethyl malonate.
Scheme 6. Routes towards (+)-taylorione and (+)-nortaylorione
using the ethylene equivalent technique in the key Khand annulation.

W.J. Kerr et al. / Journal of Organometallic Chemistry 630 (2001) 104–117
109
tenones more normally accessed when ethylene gas is
the alkene component used in the cyclisation. This
process was optimised and now constitutes a novel
method by which vinyl esters can be utilised as non-
gaseous ethylene equivalents in the Khand annulation.
The mild conditions and simple techniques employed
provide significant advantages, both in terms of practi-
cal convenience and, in the majority of cases explored,
reaction yield, over the corresponding gaseous alkene
procedures. Furthermore, the developed method was
applied as the key step in two independent natural
product syntheses: the variant of our taylorione (and
nortaylorione) synthesis described above and an effi-
cient construction of a useful radiolabelled derivative of
cis-methyl jasmonate as reported in the following
paper.
Scheme 7. Khand reaction of phenylethynehexacarbonyldicobalt with
vinyl n-butylthioacetate.
4. Experimental
4.1. General remarks
Scheme 8. Enyne substrate preparation and intramolecular Khand
reaction.
Dry THF and Et2O were obtained by distilling com-
mercial solvents from sodium benzophenone ketyl and
CH2Cl2 was distilled from calcium hydride. Light
petroleum refers to the fraction of b.p. 30–40 °C and
was distilled prior to use.
N-Methylmorpholine N-oxide (NMO) was obtained
in anhydrous form by heating at 90 °C at 0.1 mmHg or
as NMO·H2O by recrystallisation from moist acetone.
Trimethylamine-N-oxide as TMANO·2H2O, was used
as supplied, or converted to the anhydrous form by the
literature method [18]. Brucine N-oxide was prepared
as described [19]. Except as stated, all other reagents
were used as supplied.
Known hexacarbonyl(alkyne)dicobalt complexes
[(C2H2)Co2(CO)6 [20], (PhC2H)Co2(CO)6 [6a], (HO-
(CH3)2C2H)Co2(CO)6 [21], 8a [6a], 8b [6a], 8d [6a], 8e
[22], and (CH3C2CH3)Co2(CO)6 [23]] were prepared by
standard methods from free alkyne and commercial
Co2(CO)8 at room temperature (r.t.) in light petroleum
or CH2Cl2 and were purified by column chromatogra-
phy on silica. All organometallic complexes were stored
under nitrogen at, or below, −20 °C and all reactions
were performed under a nitrogen atmosphere unless
otherwise stated.
Khand reactions were carried out at various tempera-
tures with or without promoter and/or ultrasonication
(using a Vibracell VL 50 titanium horn operating at 50
W/20 kHz). Speed of addition of the promoter, if used,
was found to have a considerable effect on the yields
obtained; very slow addition was controlled by use of a
syringe pump. Anhydrous N-oxides were used in tolu-
The initial alkylation was performed with 3-chloro-
propanal diethyl acetal to yield (EtO2C)2CHCH2-
CH2CH(OEt)2 (16) [17] followed by a second alkylation
with propargyl bromide to give 17 (100%). Hydrolysis
with aqueous hydrochloric acid solution liberated the
free aldehyde 18 (99%) and treatment with acetic anhy-
dride and a catalytic quantity of K2CO3 gave the enyne
15 (77%). The resultant hexacarbonyldicobalt complex
19 underwent the Khand reaction, promoted by
NMO·H2O, with loss of acetate to give the bicyclic
keto-diester 20 as the only isolable product in 54% yield
(Scheme 8).
3. Conclusions
In summary, we have examined the use of several
vinyl ethers and esters in the Khand cyclisation reac-
tion. Using amine N-oxide promotion by itself, or in
conjunction with ultrasonication or gentle heating, both
ethyl vinyl ether and 2,3-dihydrofuran underwent the
Khand reaction and afforded the anticipated oxy-
genated cyclopentenones in reasonable yields and with
good to excellent levels of regioselectivity. In addition,
it was found that vinyl esters behaved in an unexpected
fashion when subjected to amine N-oxide promoted
Khand reaction conditions. The pathway of such reac-
tions featured a carbon–oxygen bond cleavage which
resulted in the formation of the reduced cyclopen-

110
W.J. Kerr et al. / Journal of Organometallic Chemistry 630 (2001) 104–117
4.3. Reaction of ethyl 6inyl ether with
hexacarbonyl[v-[(1,2-p:1,2-p)phenylethyne]]-
dicobalt-(CoꢁCo)
ene or CH2Cl2 solution, the hydrates more commonly
in MeOH, which is itself a weak promoter [24]. Typi-
cal procedures are outlined below and further details
are given in Tables 1 and 3.
4.3.1. Thermal reaction
1H- and 13C-NMR were run on a Bruker WM 250
and a Bruker WM 400 in CDCl3 solutions. Chemical
shifts are reported in parts per million downfield rela-
tive to Me4Si (l 0.00); coupling constants are reported
in Hz. Infrared spectra were obtained on a Mattson
1000 or Nicolet Impact 400D FTIR spectrometer in
CH2Cl2 solutions or as films. High resolution mass
spectrometry was performed on a JEOL Instruments
JMS-AX505HA mass spectrometer system or a Finni-
gan MAT 900XLT high resolution double focussing
mass spectrometer. Mass spectral data is reported as
m/z (relative intensity).
A solution of ethyl vinyl ether (0.29 ml, 220 mg,
3.0 mmol) in toluene (4 ml) was added to a solution
of hexacarbonyl[m-[(1,2-h:1,2-h)phenylethyne]]dicobalt-
(CoꢁCo) (195 mg, 0.50 mmol) in toluene (12 ml) and
the mixture heated to 70 °C for 22 h. The mixture
was then filtered through a pad of silica which re-
tained the product. The product was extracted into
Et2O and the extract evaporated under reduced pres-
sure. The crude residue was purified by column chro-
matography on silica using 50% Et2O in light
petroleum as the eluent (Rf=0.60) to give the
product as a pale yellow oil containing a mixture of
the isomers 1b and 2b (7:2) (20 mg, 20%). 5-Ethoxy-
2-phenylcyclopent-2-en-1-one (1b): 1H-NMR (250
MHz, CDCl3): l=1.29 (3H, t, J=7.0 Hz, CH3), 2.60
(1H, dt, J=18.9, 2.9 Hz, H-4), 3.06 (1H, ddd, J=
18.9, 6.6, 3.4 Hz, H-4), 3.71 (1H, dq, J=9.1, 7.0 Hz,
CH2CH3), 3.98 (1H, dq, J=9.1, 7.0 Hz, CH2CH3),
4.13 (1H, dd, J=6.6, 3.0 Hz, H-5), 7.27–7.48 (3H,
m, Ph), 7.69–7.72 (3H, m, Ph+H-3). 13C-NMR (62.5
MHz, CDCl3): l=15.5, 38.8, 66.2, 78.9, 127.0, 128.7,
128.9, 131.5, 141.6, 154.7, 205.0. IR (cm−1, CH2Cl2):
4.2. Reaction of ethyl 6inyl ether with
hexacarbonyl[v-[(1,2-p:1,2-p)ethyne]]dicobalt-(CoꢁCo)
4.2.1. n-Butyl methyl sulfide promoted reaction
A mixture of hexacarbonyl[m-[(1,2-h:1,2-h)ethyne]]-
dicobalt-(CoꢁCo) (0.21 g, 0.67 mmol), ethyl vinyl
ether (10 ml) and n-butyl methyl sulfide (0.25 g, 2.40
mmol) in 1,2-dichloroethane (10 ml) was heated under
reflux for 30 min. The mixture was filtered through a
pad of silica using Et2O as the eluent. The filtrate was
evaporated under reduced pressure to leave a residue,
which was purified by column chromatography on sil-
ica using a 10–50% Et2O in light petroleum gradient
as the eluent to give 5-ethoxycyclopent-2-en-1-one (1a)
[25] as a pale yellow oil (27.0 mg, 32%). 1H-NMR
(400 MHz, CDCl3): l=1.23 (3H, t, J=7.0 Hz, CH3),
2.53–2.59 (1H, dq, J=18.6, 2.5 Hz, H-4), 2.95–3.03
(1H, m, H-4), 3.60–3.67 (1H, m, CH2CH3), 3.84–3.95
(2H, overlapping m, CH2CH3, H-5), 6.15–6.17 (1H,
m, H-2), 7.54–7.62 (1H, m, H-3). 13C-NMR (100
MHz, CDCl3): l=15.4, 35.9, 66.1, 77.2, 132.7, 161.5,
207.5. IR (cm−1, CH2Cl2): wmax 2966, 2883, 1721,
1594.
wmax
1710.
4-Ethoxy-2-phenylcyclopent-2-en-1-one
(2b): 1H-NMR (250 MHz, CDCl3): l=1.20 (3H, t,
J=6.9 Hz, CH3), 2.03 (1H, ddd, J=14.4, 7.4, 1.4
Hz, H-5), 2.88–2.95 (1H, m, H-5), 3.58 (1H, dq, J=
9.1, 7.0 Hz, CH2CH3), 3.98 (1H, dq, J=9.1, 7.0 Hz,
CH2CH3), 4.25–4.35 (1H, m, H-4), 7.27–7.48 (3H, m,
Ph), 7.69–7.72 (3H, m, Ph+H-3).
4.3.2. Ultrasound and anhydrous NMO promoted
reaction
A mixture of ethyl vinyl ether (73 ml, 55.4 mg, 0.77
mmol), hexacarbonyl[m - [(1,2 - h:1,2 - h)phenylethyne]]-
dicobalt-(CoꢁCo) (1.00 g, 0.26 mmol), NMO (273 mg,
2.32 mmol) and toluene (10 ml) was subjected to ul-
trasonication for 25 min. The same product mixture
(16 mg, 31%) was isolated as before.
4.3.3. NMO·H2O promoted reaction
4.2.2. Ultrasound and TMANO·2H2O promoted
reaction
A solution of N-methylmorpholine N-oxide mono-
hydrate (1.25 g, 9.30 mmol) in CH2Cl2 (20 ml) was
added over a 30 min period to a stirred mixture of
hexacarbonyl[m - [(1,2 - h:1,2 - h)phenylethyne]]dicobalt-
(CoꢁCo) (0.36 g, 0.93 mmol) and ethyl vinyl ether (5
ml) at 25 °C. The mixture was stirred for 60 h before
it was filtered through a pad of silica using CH2Cl2 as
the eluent. The filtrate was evaporated under reduced
pressure to leave a crude residue, which was purified
by column chromatography on silica using a 0–40%
Et2O in light petroleum gradient as the eluent to give
5-ethoxy-2-phenylcyclopent-2-en-1-one (1b) (0.08 g,
43%) as a pale yellow oil.
A mixture of hexacarbonyl[m-[(1,2-h:1,2-h)ethyne]]-
dicobalt-(CoꢁCo) (0.38 g, 1.23 mmol), ethyl vinyl
ether (10 ml) and TMANO·2H2O (1.36 g, 12.3 mmol)
in toluene (20 ml) was sonicated for 2 h. The mixture
was then filtered through a pad of silica using Et2O
as the eluent. The filtrate was evaporated under re-
duced pressure to leave a crude residue, which was
purified by column chromatography on silica using a
10–50% Et2O in light petroleum gradient as the elu-
ent to give the product 1a as a pale yellow oil (50.0
mg, 32%). Analytical data were as above.

W.J. Kerr et al. / Journal of Organometallic Chemistry 630 (2001) 104–117
111
4.6. Reaction of 2,3-dihydrofuran with
hexacarbonyl[v-[(1,2-p:1,2-p)phenylethyne]]-
dicobalt-(CoꢁCo)
4.4. Reaction of ethyl 6inyl ether with
hexacarbonyl[v-[(3,4-p:3,4-p)-2-methylbut-3-yn-2-ol]]-
dicobalt-(CoꢁCo)
4.4.1. Ultrasound and TMANO·2H2O promoted
reaction
4.6.1. TMANO·2H2O promoted reaction
A solution of TMANO·2H2O (260 mg, 2.11 mmol) in
MeOH (1 ml) was added over a 25 min period to a
solution of 2,3-dihydrofuran (58 ml, 55 mg, 0.77 mmol)
and hexacarbonyl[m - [(1,2 - h:1,2 - h)phenylethyne]]-
dicobalt-(CoꢁCo) (100 mg, 0.26 mmol) in toluene (10
ml) at 25 °C. The mixture was then warmed to 40 °C
for 2 h. Work-up was the same as in the preceding
experiments. Chromatographic purification used 20%
light petroleum in Et2O as the eluent (Rf=0.40) to give
2,3,3a,6a - tetrahydro - 5 - phenyl - 6H - cyclopenta[b]furan-
A
mixture of ethyl vinyl ether (2.5 ml),
hexacarbonyl[m-[(3,4-h:3,4-h)-2-methylbut-3-yn-2-ol]]-
dicobalt-(CoꢁCo) (105 mg, 0.28 mmol), toluene (7.5 ml)
and TMANO·2H2O (200 mg, 2.52 mmol) in MeOH (2
ml) was sonicated for 85 min. The mixture was then
filtered through a pad of kieselguhr, which was washed
with CH2Cl2. The combined filtrate and washings were
evaporated under reduced pressure to leave a brown
oil, which was purified by column chromatography on
silica using 20% light petroleum in Et2O as the eluent
(Rf (Et2O)=0.45) to give 5-ethoxy-2-(1-hydroxy-1-
methylethyl)cyclopent-2-en-1-one (1c) (18 mg, 35%) as a
1
6-one (3b) (26 mg, 52%) as a yellow oil. H-NMR (250
MHz, CDCl3): l=1.90 (1H, ddt, J=12.5, 5.3,
1.9 Hz, H-3), 2.18 (1H, dddd, J=12.5, 10.8, 9.8,
7.5 Hz, H-3), 3.54 (1H, dddd, J=11.0, 9.7, 5.5, 2.0 Hz,
H-3a), 3.58 (1H, ddd, J=11.0, 9.2, 5.5 Hz, H-2),
4.03 (1H, ddd, J=11.0, 7.5, 2.0 Hz, H-2), 4.49 (1H, d,
J=5.7 Hz, H-6a), 7.27–7.41 (3H, m, ArꢁH), 7.71–
7.74 (3H, m, ArꢁH+H-4). 13C-NMR (62.5 MHz,
CDCl3): l=30.6, 42.3, 67.6, 81.4, 127.1, 128.7,
129.9, 130.8, 143.6, 158.2, 204.9. IR (cm−1, CH2Cl2):
wmax 1720.
1
pale yellow oil. H-NMR (250 MHz, CDCl3): l=1.30
(3H, t, J=7.0 Hz, CH3CH2), 1.46 (6H, s, C(CH3)2),
2.45 (1H, dt, J=18.4, 2.8 Hz, H-4), 2.85 (1H, ddd,
J=18.4, 6.6, 3.2 Hz, H-4), 3.30 (1H, br s, OH), 3.66
(1H, dq, J=9.0, 7.0 Hz, CH2CH3), 3.86 (1H, dq,
J=9.0, 7.0 Hz, CH2CH3), 3.99 (1H, dd, J=6.4, 2.8
Hz, H-5), 7.30 (1H, t, J=2.6 Hz, H-3). 13C-NMR (62.5
MHz, CDCl3): l=15.5, 28.7, 28.8, 33.6, 66.3, 69.9,
78.6, 149.7, 152.5, 207.3. IR (cm−1, CH2Cl2): wmax 1709.
4.7. Reaction of 2,3-dihydrofuran with
hexacarbonyl[v-[(3,4-p:3,4-p)-2-methylbut-3-yn-2-ol]]-
dicobalt-(CoꢁCo)
4.5. Reaction of 2,3-dihydrofuran with
hexacarbonyl[v-[(1,2-p:1,2-p)ethyne]]dicobalt-(CoꢁCo)
4.5.1. NMO·H2O promoted reaction
A solution of NMO·H2O (1.00 g, 7.41 mmol) in
CH2Cl2 (20 ml) was added, over a 1 h period, to a
solution of hexacarbonyl[m - [(1,2 - h:1,2 - h)ethyne]]-
dicobalt-(CoꢁCo) (0.22 g, 0.70 mmol) in a mixture of
CH2Cl2 (10 ml) and 2,3-dihydrofuran (20 ml) at 25 °C.
The mixture was stirred for 16 h before it was filtered
through a pad of silica using Et2O as the eluent. The
filtrate was evaporated under reduced pressure to leave
a crude residue, which was purified by column chro-
matography on silica using a 10–80% Et2O in light
petroleum gradient as the eluent to give 2,3,3a,6a-te-
trahydro-6H-cyclopenta[b]furan-6-one (3a) as a pale yel-
4.7.1. Ultrasound and TMANO·2H2O promoted
reaction
A mixture of 2,3-dihydrofuran (4.0 ml), hexacar-
bonyl[m-[(3,4-h:3,4-h)-2-methylbut-3-yn-2-ol]]dicobalt-
(CoꢁCo) (200 mg, 0.54 mmol), TMANO·2H2O (540
mg, 4.86 mmol) in MeOH (1.5 ml) and toluene (12 ml)
was sonicated for 30 min and worked up as in the
previous experiments. The product, 2,3,3a,6a-tetra-
hydro-5-(1-hydroxy-1-methylethyl)-6H-cyclopenta[b]-
furan-6-one (3c) (49 mg, 49%), was eluted with Et2O
(Rf=0.30). 1H-NMR (250 MHz, CDCl3): l=1.44 (6H,
s, C(CH3)2), 1.83 (1H, ddt, J=12.5, 9.5, 5.1 Hz, H-3),
2.09 (1H, dddd, J=12.5, 10.8, 9.8, 7.5 Hz, H-3), 3.42
(1H, dddd, J=10.4, 9.5, 5.4, 1.8 Hz, H-3a), 3.52 (1H,
ddd, J=10.9, 9.5, 5.4 Hz, H-2), 4.00 (1H, ddd, J=
10.9, 7.5, 1.8 Hz, H-2), 4.35 (1H, d, J=5.6 Hz, H-6a),
7.27 (1H, d, J=2.8 Hz, H-4). 13C-NMR (62.5 MHz,
CDCl3): l=28.7, 28.8, 30.3, 42.2, 67.6, 69.8, 81.1,
152.2, 156.0, 206.7. IR (cm−1, CH2Cl2): wmax 1709.
HRMS: m/z: Found: 182.0957 (100). Calc. for
C10H14O3 [M+]: 182.0943.
1
low oil (41.0 mg, 48%). H-NMR (400 MHz, CDCl3):
l=1.77–1.82 (1H, m), 2.00–2.13 (1H, m), 3.47–3.55
(2H, m), 3.94–3.98 (1H, m), 4.26 (1H, d, J=5.6 Hz),
6.23 (1H, dd, J=5.9, 1.7 Hz), 7.58 (1H, dd, J=5.9, 2.8
Hz). 13C-NMR (62.5 MHz, CDCl3): l=30.1, 44.9,
67.5, 79.6, 134.7, 164.6, 207.2. IR (cm−1, CH2Cl2): wmax
2966, 2883, 1721, 1593, 1357, 1191, 1089. HRMS: m/z:
Found: 124.05292 (100). Calc. for C7H8O2 [M+]:
124.05243.

112
W.J. Kerr et al. / Journal of Organometallic Chemistry 630 (2001) 104–117
of silica using CH2Cl2 as the eluent. The filtrate was
evaporated under reduced pressure to leave a crude
residue, which was purified by filtration through a
second pad of silica using 10% Et2O in light petroleum
as the eluent to give hexacarbonyl[v-[(1,2-p:1,2-p)-4-
(tetrahydropyran-2-yloxy)but-1-yne]]dicobalt-(CoꢁCo)
4.8. Reactions of 6inyl esters and 6inyl bromide
4.8.1. Reactions with
hexacarbonyl[v-[(1,2-p:1,2-p)phenylethyne]]-
dicobalt-(CoꢁCo)
General: reactions proceeding with reductive cleavage
of the halo- or ester group are collected in Table 1. The
best procedure follows.
A solution of NMO·H2O (1.32 g, 9.78 mmol) in
CH2Cl2 (30 ml) was added over 3 h (syringe pump) to
1
(8c) (3.02 g, 96%) as a red oil. H-NMR (400 MHz,
CDCl3): l=1.52–1.65 (4H, m), 1.75 (1H, m) 1.84 (1H,
m), 3.16 (2H, m), 3.53 (1H, m, CH2CH2CH2O), 3.61
(1H, m, CH2CH2CH2O), 3.88 (1H, m, CCH2CH2O),
4.00 (1H, m, CCH2CH2O), 4.63 (1H, t, J=2.9 Hz,
OCHO), 6.04 (1H, s, ꢀCH). 13C-NMR (100 MHz,
CDCl3): l=19.7, 25.6, 30.7, 34.3, 62.6, 67.5, 73.8
(CH2CꢀCH), 85.2 (CH2CꢀCH), 99.0 (OCHO), 200.0
(CO). IR (cm−1, film) wmax 2097, 2059, 2010. HRMS:
m/z: Found: 383.94615. Calc. for C13H14Co2O6 [M+−
2CO]: 383.94543.
a
stirred solution of hexacarbonyl[m-[(1,2-h:1,2-
h)phenylethyne]]dicobalt-(CoꢁCo) (380 mg, 0.98 mmol)
in vinyl benzoate (3.00 g, 20 mmol) at 25 °C. The
mixture was stirred for a further 16 h. Cobalt salts were
removed from the resultant purple mixture by filtration
through a 1 cm pad of silica using CH2Cl2 as the eluent.
The yellow–brown filtrate was evaporated under re-
duced pressure to leave a crude residue which was
purified by column chromatography on silica using a
0–40% Et2O in light petroleum gradient as the eluent.
Concentration of the first fraction, followed by distilla-
tion led to recovery of vinyl benzoate (2.50 g). 2-
Phenylcyclopent-2-en-1-one (7) was eluted next as a
pale yellow oil which solidified on standing (120 mg,
4.8.2.2. Hexacarbonyl[v-[(3,4-p:3,4-p)but-3-yn-1-ol]]-
dicobalt-(CoꢁCo) (8f). But-3-yn-1-ol (2.20 g, 31.4
mmol) in CH2Cl2 (10 ml) was added over a 10 min
period to a stirred solution of octacarbonyldicobalt
(10.9 g, 31.9 mmol) in CH2Cl2 (40 ml) at 25 °C. The
mixture was stirred for 5 h before it was filtered
through a pad of silica using 50% Et2O in light
petroleum as the eluent. The filtrate was evaporated
under reduced pressure and the residue was purified by
column chromatography on silica using: 50% Et2O in
light petroleum as eluent to give hexacarbonyl[m-[(3,4-
p:3,4-p)but-3-yn-1-ol]]dicobalt-(CoꢁCo) (8f) (5.00 g,
1
80%), m.p. 68–69 °C [lit. [4,6,26] 71–72 °C]. H-NMR
(400 MHz, CDCl3): l=2.52 (2H, m, H-5), 2.63 (2H, m,
H-4), 7.27–7.44 (3H, m, ArꢁH), 7.68 (2H, d, J=7.3
Hz, ArꢁH), 7.76 (1H, m, H-3). 13C-NMR (100 MHz,
CDCl3): l=26.4, 36.0, 127.2, 128.5, 128.6, 131.9,
159.1, 207.0. IR (cm−1, film): wmax 3038, 1707.
1
99%) as a red oil. H-NMR (400 MHz, CDCl3): l=
1.67 (1H, t, J=5.0 Hz, HO), 3.12 (2H, dt, J=6.5, 1.1
Hz, CH2CH2OH), 3.90 (2H, app q, J=6.5 Hz,
CH2CH2OH), 6.07 (1H, t, J=1.1 Hz, ꢀCH). 13C-NMR
(100 MHz, CDCl3): l=36.8 (CH2CH2OH), 63.5
(CH2CH2OH), 73.7 (CH2CꢀCH), 91.3 (CH2CꢀCH),
202.4 (CO). IR (cm−1, film): wmax 3407, 2094, 2068,
2027. HRMS: m/z: Found: 327.88227. Calc. for
C9H6Co2O6 [M+−CO]: 327.88283.
4.8.2. Reactions of 6inyl esters with selected
hexacarbonyl(alkyne)dicobalt complexes
The general method outlined above for the
phenylethyne complex was applied to a series of other
complexes as detailed here and in Table 3.
4.8.2.1. Hexacarbonyl[v-[(1,2-p:1,2-p)-4-(tetrahydropy-
ran-2-yloxy)but-1-yne]]dicobalt-(CoꢁCo) (8c). A solu-
tion of 2-(but-3-ynyloxy)tetrahydro-2H-pyran [27] (1.10
g, 7.14 mmol) in CH2Cl2 (20 ml) was added over a 10
min period to a stirred solution of Co2(CO)8 (2.35 g,
6.87 mmol) in CH2Cl2 (30 ml) at 25 °C. The mixture
was stirred for 2 h before it was filtered through a pad
4.8.2.3. 2-(2-(Tetrahydropyran-2-yloxy)ethyl)cyclopent-
2-en-1-one (9c). A solution of NMO·H2O (1.50 g, 11.1
mmol) in CH2Cl2 (20 ml) was added over a 1 h period
(syringe pump) to a stirred solution of hexacarbonyl[m-
Table 3
Additional Khand reactions of alkynehexacarbonyldicobalt complexes with vinyl benzoate a
Entry
Complexed alkyne
Identity
Vinyl benzoate (g)
NMO·2H2O
DCM
(ml)
Yield
(mg)
References
(mg)
(mmol)
(g)
(mmol)
(%)
1
2
3
4
5
8a
8b
8d
520
440
340
770
300
1.36
1.04
0.85
1.98
0.61
3.00
3.00
3.00
3.00
5.00
1.84
1.40
1.20
3.00
0.82
13.6
10.37
8.89
22.22
6.07
30
30
20
40
30
160
180
64
10.9
100
77
87
45
5
[6a]
[6a]
[6a]
[29]
[6a]
2-Butyne·Co2(CO)6
10
60
a All reactions were performed at room temperature over 16 h.

W.J. Kerr et al. / Journal of Organometallic Chemistry 630 (2001) 104–117
113
[(1,2-h:1,2-h)-4-(tetrahydropyran-2-yloxy)but-1-yne]]-
dicobalt-(CoꢁCo) (8c) (0.58 g, 1.32 mmol) in vinyl
benzoate (10 ml) at 25 °C. The mixture was stirred for
16 h before it was filtered through a pad of silica using
Et2O as the eluent. The filtrate was evaporated under
reduced pressure to leave a crude residue which was
purified by column chromatography on silica using a
10–50% Et2O in light petroleum gradient as the eluent
to give 2-(2-(tetrahydropyran-2-yloxy)ethyl)cyclopent-2-
a pad of silica using Et2O as the eluent. The filtrate was
evaporated under reduced pressure to leave a crude
residue, which was purified by column chromatography
on silica using a 10–100% Et2O in light petroleum
gradient as the eluent to give 2-(2-hydroxy-
ethyl)cyclopent-2-en-1-one (9f) (1.30 g, 61%) as a pale
1
yellow oil. H-NMR (400 MHz, CDCl3): l=2.42 (2H,
m, H-5), 2.47 (2H, t, J=5.8 Hz, CH2CH2OH), 2.60
(2H, m, H-4), 2.83 (1H, s, OH), 3.71 (2H, t, J=5.8 Hz,
CH2CH2OH), 7.50 (1H, s, H-3). 13C-NMR (100 MHz,
CDCl3): l=27.0, 29.2, 34.7, 61.2 (CH2OH), 143.9 (C-
2), 160.6 (C-3), 211.3 (C-1). IR (cm−1, film): wmax 3400,
1664. HRMS: m/z: Found: 126.06816. Calc. for
C7H10O2 [M+]: 126.06808.
1
en-1-one (9c) (0.22 g, 80%) as a pale yellow oil. H-
NMR (400 MHz, CDCl3): l=1.47 (4H, m), 1.63 (1H,
m), 1.75 (1H, m), 2.33 (2H, m), 2.42 (2H, m), 2.54 (2H,
m), 3.46 (2H, m), 3.78 (2H, m), 4.54 (1H, t, J=2.9 Hz,
OCHO), 7.42 (1H, s, H-3). 13C-NMR (100 MHz,
CDCl3): l=19.8, 25.4, 25.6, 26.8, 30.8, 34.4, 62.6, 65.4,
99.0, 143.5, 159.1, 209.8. IR (cm−1, film): wmax 1702,
1625. HRMS: m/z: Found: 210.12722. Calc. for
C12H18O3 [M+]: 210.12559.
(b) Pyridinium p-toluenesulfonate (0.21 g, 0.86
mmol) was added to a solution of 2-(2-(tetrahydropy-
ran-2-yloxy)ethyl)cyclopent-2-en-1-one (9c) (1.80 g, 8.57
mmol) in MeOH (60 ml) and the mixture heated under
reflux for 1 h. The solvent was then evaporated under
reduced pressure to leave a crude residue, which was
purified by column chromatography on silica using
Et2O as the eluent to give 2-(2-hydroxyethyl)cyclopent-
2-en-1-one (9f) (1.02 g, 95%) as a pale yellow oil.
Analytical data were identical with the above sample.
2,3-Dimethylcyclopent-2-en-1-one [29] was obtained
4.8.2.4. 2-(2-Hydroxymethyl)cyclopent-2-en-1-one (9e)
[28]. (a) A solution of N-methylmorpholine N-oxide
monohydrate (1.38 g, 10.2 mmol) in CH2Cl2 (20 ml) was
added over a 2 h period to a stirred solution of hexacar-
bonyl[m - [(2,3 - h:2,3 - h)prop - 2 - yn - 1 - ol]dicobalt-
(CoꢁCo) (8e) (0.35 g, 1.02 mmol) in vinyl benzoate (3.00
g, 20.3 mmol) at 25 °C. The mixture was stirred for a
further 16 h before it was filtered through a pad of silica
using Et2O as the eluent. The filtrate was evaporated
under reduced pressure to leave a crude residue, which
was purified by column chromatography on silica using
a 20–100% Et2O in light petroleum gradient as the
eluent to give 2-hydroxymethylcyclopent-2-en-1-one
1
as a colourless oil. H-NMR (400 MHz, CDCl3): l=
1.70 (3H, s, CH3), 2.05 (3H, s, CH3), 2.37 (2H, m, H-5),
2.49 (2H, m, H-4). IR (cm−1, film): wmax 2971, 2914,
1698, 1650.
4.9. Reaction of 6inyl acetate with
hexacarbonyl[v-[(1,2-p:1,2-p)phenylethyne]]-
dicobalt-(CoꢁCo) in air
1
(9e) (37.0 mg, 33%) as a colourless oil. H-NMR (400
MHz, CDCl3): l=2.45 (2H, m, H-5), 2.52 (1H, s, OH),
2.64 (2H, m, H-4), 4.37 (2H, s, CH2OH), 7.54 (1H, app
t, J=1.2 Hz, H-3). IR (cm−1, film): wmax 3450, 3025,
2930, 1700, 1645.
A solution of TMANO·2H2O (0.84 g, 7.57 mmol) in
MeOH (30 ml) was added over a 15 min period to a
stirred solution of hexacarbonyl[m-[(1,2-h:1,2-h)-
phenylethyne]]dicobalt-(CoꢁCo) (500 mg, 1.46 mmol) in
vinyl acetate (10 ml) at 25 °C, under an air atmosphere.
The mixture was stirred for 16 h before it was filtered
through a pad of silica using Et2O as the eluent. The
filtrate was evaporated under reduced pressure to leave
a crude residue, which was purified by column chro-
matography on silica using a 0–50% Et2O in light
petroleum gradient as the eluent to give 5-acetoxy-2-
phenylcyclopent-2-en-1-one (5b) (20.3 mg, 7%) as a pale
yellow oil; no 2-phenylcyclopent-2-en-1-one was ob-
(b) Pyridinium para-toluenesulfonate (0.12 g, 0.48
mmol) was added to a solution of 2-((tetrahydro-2H-
pyran-2-yloxy)methyl)cyclopent-2-en-1-one (9b) (0.95 g,
4.8 mmol) in MeOH (50 ml) and the mixture was heated
under reflux for 1 h. The solvent was then evaporated
under reduced pressure to leave a crude residue, which
was purified by filtration through a pad of silica using
Et2O as the eluent to give 2-hydroxymethylcyclopent-2-
en-1-one (9e) (0.54 g, 99%) as a white crystalline solid.
Analytical data were identical with the above sample.
1
tained. H-NMR (400 MHz, CDCl3): l=2.19 (3H, s,
CH3CO), 2.67 (1H, m, H-4), 3.23 (1H, ddd, J=19, 7.0,
3.4 Hz, H-4), 5.33 (1H, dd, J=7.0, 3.3 Hz, H-5), 7.38
(3H, m, ArꢁH), 7.74 (3H, m, ArꢁH+H-3). 13C-NMR
(100 MHz, CDCl3): l=21.0 (C-4), 33.6 (CH3CO), 73.2
(C-5), 127.1 (ArꢁC), 128.8 (ArꢁC), 129.1 (ArꢁC), 130.9
(ArꢁC), 143.0 (C-2), 154.6 (C-3). 169.5 (CH3CO), 201.2
(C-1). IR (cm−1, film): wmax 1715, 1651. HRMS: m/z:
Found: 200.08551. Calc. for C13H12O2 [M+−O]:
200.08373.
4.8.2.5. 2-(2-Hydroxyethyl)cyclopent-2-en-1-one (9f).
(a) A solution of N-methylmorpholine N-oxide mono-
hydrate (20.0 g, 0.15 mol) in CH2Cl2 (300 ml) was
added over a 30 min period (dropping funnel) to a
stirred solution of hexacarbonyl[m-[(3,4-h:3,4-h)but-3-
yn-1-ol]]dicobalt-(CoꢁCo) (8f) (4.00 g, 16.8 mmol) in
vinyl benzoate (70 ml) at 25 °C. The mixture was
stirred for a further 16 h before it was filtered through

114
W.J. Kerr et al. / Journal of Organometallic Chemistry 630 (2001) 104–117
4.10. Reaction of 6inyl acetate with
hexacarbonyl[v-[(1,2-p:1,2-p)phenylethyne]]-
dicobalt-(CoꢁCo) under ‘dry’ conditions
2-oxopropyl)phosphonate [12] (1.50 g, 7.81 mmol) in
MeOH (100 ml) at 25 °C. The mixture was stirred for
16 h before the solvent was evaporated under reduced
pressure. The residue was partitioned between ether
(100 ml) and saturated aqueous NaHCO3 (100 ml). The
organic phase was dried and evaporated under reduced
pressure and the residue chromatographed on silica
using a 0–50% ether in light petroleum gradient as the
eluent to give (1R,3R)-cis-1-ethynyl-2,2-dimethyl-3-(2-
(2-methyl-1,3-dioxolan-2-yl)ethyl)cyclopropane (0.84 g,
85%) as a pale yellow oil. 1H-NMR (250 MHz,
CDCl3): l=0.77 (1H, dt, J=8.5, 7.1 Hz, CHCH2),
1.07 (3H, s, CH3), 1.11 (3H, s, CH3), 1.17 (3H, dd,
J=8.6 2.3 Hz, CHꢁCꢀ), 1.35 (3H, s, CH3COOCH2),
1.56–1.70 (4H, m, CHCH2CH2), 1.89 (1H, d, J=2.2
Anhydrous NMO (1.50 g, 12.9 mmol) was dissolved
in CH2Cl2 (20 ml) and added over 1 h to a stirred
solution
of
hexacarbonyl[m-[(1,2-h:1,2-h)-phenyl-
ethyne]]dicobalt-(CoꢁCo) (500 mg, 1.29 mmol) in vinyl
acetate (5 ml) at 25 °C. The mixture was stirred for 5 h,
then filtered through a pad of silica using Et2O as the
eluent. The filtrate was evaporated under reduced pres-
sure to leave a crude residue, which was purified by
column chromatography on silica using a 0–50% Et2O
in light petroleum gradient as the eluent to give 2-
phenylcyclopent-2-en-1-one (7) (61.1 mg, 30%) followed
by 5-acetoxy-2-phenylcyclopent-2-en-1-one (5b), ad-
mixed with 4-acetoxy-2-phenylcyclopent-2-en-1-one
(6b) [30] (ꢀ1:1) (10 mg, 4%) which failed to separate
adequately on this scale; only the faster moving isomer
5b could be obtained in pure form. Analytical data for
5b were as given above.
Hz, HCꢀ), 3.86–4.02 (4H, m, OCH2CH2O). IR (cm−1
film): wmax 3310, 2978, 2953, 2927, 2110, 1472.
,
4.12.2. Hexacarbonyl[(1S,3R)-cis-1-[v-[(1,2-p:1,2-p)-
ethynyl]]-2,2-dimethyl-3-(2-(2-methyl-1,3-dioxolan-
2-yl)ethyl)cyclopropane]dicobalt-(CoꢁCo) (10) [6]
A solution of (1R,3R)-cis-1-ethynyl-2,2-dimethyl-3-
(2-(2-methyl-1,3-dioxolan-2-yl)ethyl)cyclopropane (0.85
g, 4.09 mmol) in light petroleum (20 ml) was added to
a stirred solution of octacarbonyldicobalt (1.40 g, 4.09
mmol) in the same solvent over 10 min at 25 °C. After
being stirred for 2 h the mixture was filtered through a
pad of silica, eluting with 50% ether–light petroleum.
The solution was evaporated under reduced pressure
and the residue purified by chromatography on silica
using a 0–30% ether in light petroleum gradient to
elute the complex hexacarbonyl[(1S,3R)-cis-1-[m-[(1,2-
h:1,2 - h)ethynyl]] - 2,2 - dimethyl - 3 - (2 - (2 - methyl - 1,3-
dioxolan-2-yl)ethyl)cyclopropane]dicobalt-(CoꢁCo) (10)
(2.00 g, 99%) as a red oil. 1H-NMR (250 MHz, CDCl3):
l=0.86 (1H, m, CHCH2), 1.07 (3H, s, CH3), 1.18 (3H,
s, CH3), 1.33 (3H, s, CH3COOCH2), 1.59–1.72 (4H,
overlapping m, CHCH2CH2), 2.08 (1H, dd, J=8.1, 0.7
Hz, CHꢁCꢀ), 3.81–4.02 (4H, overlapping m,
OCH2CH2O), 5.84 (1H, d, J=0.9 Hz, HCꢀ). IR
(cm−1, film): wmax 2989, 2951, 2884, 2095, 2057, 2019,
1588.
4.11. Reaction of 6inyl benzoate with
hexacarbonyl[v-[(1,2-p:1,2-p)phenylethyne]]-
dicobalt-(CoꢁCo) in the presence of D2O
A solution of anhydrous N-methylmorpholine N-ox-
ide (0.95 g, 8.15 mmol) in dry CH2Cl2 (20 ml) was
added over 1 h to a mixture of hexacarbonyl[m-[(1,2-
h:1,2-h)phenylethyne]]dicobalt-(CoꢁCo) (310 mg, 0.80
mmol), vinyl benzoate (1.30 g, 8.00 mmol) and D2O (1
ml) at 25 °C. The mixture was stirred for 16 h, then
filtered through a pad of silica using CH2Cl2 as the
eluent. The filtrate was evaporated under reduced pres-
sure to leave a crude residue, which was purified by
column chromatography on silica 0–40% Et2O in light
petroleum gradient as the eluent to give 2-phenyl-5-
deuteriocyclopent-2-en-1-one (80 mg, 62%) as a pale
1
yellow oil. H-NMR (400 MHz, CDCl3): l=2.59 (1H,
m, H-5), 2.72 (2H, m, H-4), 7.40 (3H, m, ArꢁH), 7.71
(2H, m, ArꢁH), 7.89 (1H, m, H-3). 13C-NMR (100
MHz, CDCl3): l=26.3 (C-4), 35.7 (t due to D-split-
ting, C-5), 127.3 (ArꢁC), 128.5 (ArꢁC), 128.6 (ArꢁC),
131.9 (ArꢁC), 143.8 (C-2), 159.1 (C-3), 208.0 (C-1). IR
(cm−1, film): wmax 3049, 1706. HRMS: m/z: Found:
159.07878. Calc. for C11H9DO [M+]: 159.07944.
4.12.3. (1S,3R)-cis-1-(Cyclopent-2-en-1-on-2-yl)-
2,2-dimethyl-3-(2-(2-methyl-1,3-dioxolan-2-yl)ethyl)-
cyclopropane (11) [6]
A solution of N-methylmorpholine N-oxide monohy-
4.12. Synthesis of the (+)-taylorione (and
(+)-nortaylorione) precursor 11 [6]
drate (0.82 g, 6.07 mmol) in CH2Cl2 (30 ml) was added
over
a
2
h
period to
a
stirred solution of
hexacarbonyl[(1S,3R)-cis-1-[m-[(1,2-h:1,2-h)ethynyl]]-
2,2-dimethyl-3-(2-(2-methyl-1,3-dioxolan-2-yl)ethyl)-
cyclopropane]dicobalt-(CoꢁCo) (10) (0.30 g, 0.61
mmol) in vinyl benzoate (5.00 g, 33.8 mmol) at 25 °C.
The mixture was stirred for a further 16 h and then
filtered through a pad of silica using CH2Cl2 as eluent.
The filtrate was evaporated under reduced pressure
4.12.1. (1R,3R)-cis-1-Ethynyl-2,2-dimethyl-3-
(2-(2-methyl-1,3-dioxolan-2-yl)ethyl)cyclopropane [6]
Potassium carbonate (2.20 g, 15.9 mmol) was added
to a stirred solution of (1S,3R)-cis-2,2-dimethyl-3-(2-(2-
methyl - 1,3 - dioxolan - 2 - yl)ethyl)cyclopropanecarbox-
aldehyde [6] (1.00 g, 4.72 mmol) and dimethyl (1-diazo-

W.J. Kerr et al. / Journal of Organometallic Chemistry 630 (2001) 104–117
115
1644, 1465, 1407. HRMS: m/z: Found: 175.07986.
Calc. for C8H15O2S [M++1]: 175.07928.
and the residue subjected to chromatography on silica
using a 0–40% ether in light petroleum gradient as
eluent to give (1S,3R)-cis-1-(cyclopent-2-en-1-on-2-yl)-
2,2-dimethyl-3-(2-(2-methyl-1,3-dioxolan-2-yl)ethyl)-
cyclopropane (11) as a colourless oil (0.10 g, 60%).
1H-NMR (400 MHz, CDCl3): l=0.97 (3H, s, CH3),
1.16 (3H, s, CH3), 1.27 (3H, s, CH3COOCH2), 1.10–
1.46 (6H, overlapping m, CHꢁCꢂ+CHCH2CH2), 2.35
(2H, m, CH2CꢂO), 2.57 (2H, m, CH2CHꢂC), 3.81–4.01
(4H, overlapping m, OCH2CH2O), 7.24 (1H, m,
CH2CHꢂC). IR (cm−1, film): wmax 2989, 2957, 2893,
1704, 1627, 1455.
4.15. Reaction of 6inyl n-butylthioacetate (14) with
hexacarbonyl[v-[(1,2-p:1,2-p)phenylethyne]]-
dicobalt-(CoꢁCo)
A solution of N-methylmorpholine N-oxide monohy-
drate (0.97 g, 7.18 mmol) in CH2Cl2 (30 ml) was added
over a 2 h period to a stirred mixture of hexacar-
bonyl[m-[(1,2-h:1,2-h)phenylethyne]]dicobalt-(CoꢁCo)
(0.28 g, 0.72 mmol) and vinyl n-butylthioacetate (14)
(2.00 g, 11.5 mmol) at 25 °C. The mixture was stirred
for a further 16 h before it was filtered through a pad
of silica using CH2Cl2 as the eluent. The filtrate was
evaporated under reduced pressure to leave a crude
residue, which was purified by column chromatography
on silica using a 0–40% Et2O in light petroleum gradi-
ent as the eluent to give 2-phenylcyclopent-2-en-1-one
(7) (68.0 mg, 60%) as a pale yellow oil. Analytical data
were as given above.
4.13. n-Butylthioacetic acid [31]
A solution of sodium chloroacetate (208.0 g, 1.80
mol) in water (700 ml) was slowly added to a solution
of 1-butanethiol (153.0 g, 1.70 mol) in aqueous NaOH
solution (5.7 M, 300 ml) at 0 °C. After the addition
was complete the mixture was heated under reflux for 1
h before it was allowed to cool and was acidified with
aqueous HCl solution to pH 1. The n-butylthioacetic
acid separated as an oily layer on top of the aqueous
phase and was extracted using Et2O (3×300 ml). The
organic phase was dried and evaporated under reduced
pressure to yield n-butylthioacetic acid (230 g, 90%) as
a clear liquid. Analytical data were identical with those
previously published. 1H-NMR (400 MHz, CDCl3):
l=0.93 (3H, t, J=7.4 Hz, CH3), 1.42 (2H, m, CH2),
1.60 (2H, m, CH2), 2.67 (2H, t, J=7.3 Hz, CH2S), 3.26
(2H, s, SCH2CO2). IR (cm−1, film): wmax 3661–2346
(br, OꢁH), 2685, 2563, 1695, 1427.
4.16. Diethyl 7,7-diethoxyhept-1-yne-4,4-dicarboxylate
(17)
A solution of n-BuLi in hexanes (8.00 ml, 2.5 M, 19.9
mmol) was added dropwise over a 10 min period to a
stirred solution of N,N-diisopropylamine (2.01 g, 19.9
mmol) in THF (75 ml) at 0 °C. The solution of lithium
N,N-diisopropylamide was then cooled to −75 °C and
a solution of diethyl 1,1-diethoxypropane-3,3-dicar-
boxylate [17] (5.24 g, 18.1 mmol) in THF (75 ml) was
added over a 20 min period. The mixture was stirred
for 30 min before propargyl bromide (80% in toluene,
3.00 g, 20.0 mmol) was added. The mixture was then
stirred for a further 30 min before it was quenched by
the addition of saturated aqueous ammonium chloride
solution (10 ml) and allowed to warm to r.t. The
solvent was evaporated under reduced pressure to leave
a residue which was partitioned between Et2O (150 ml)
and saturated aqueous ammonium chloride solution
(100 ml). The organic phase was dried and evaporated
under reduced pressure to give diethyl 7,7-diethoxyhept-
1-yne-4,4-dicarboxylate (17) (5.94 g, 100%) as a pale
4.14. Vinyl n-butylthioacetate (14)
According to the method of Swern and Jordan [32]:
mercuric acetate (1.60 g, 5.02 mmol) and 100% sulfuric
acid (0.15 ml) were added to a solution of n-butylth-
ioacetic acid (59.2 g, 0.40 mol) in vinyl acetate (206.0 g,
2.40 mol). The mixture was heated under reflux for 3 h
before the reaction was quenched by the addition of
AcONa (1.00 g, 0.01 mol). The mixture was then
partitioned between aqueous potassium carbonate solu-
tion (300 ml) and CH2Cl2 (300 ml). The organic phase
was dried and evaporated under reduced pressure to
yield 6inyl n-butylthioacetate 14 (33 g, 47%) as a clear
1
yellow oil. H-NMR (400 MHz, CDCl3): l=1.20 (6H,
t, J=7.2 Hz, 2×CH3), 1.26 (6H, t, J=7.2 Hz, 2×
CH3), 1.50 (2H, m, H-6), 1.98 (1H, t, J=2.7 Hz, HCꢀ),
2.09 (2H, m, H-5), 2.77 (2H, t, J=2.7 Hz, H-3), 3.46
(2H, m, OCH2), 3.60 (2H, m, OCH2), 4.18 (4H, m,
2×OCH2), 4.46 (1H, t, J=5.7 Hz, O2CH). 13C-NMR
(100 MHz, CDCl3): l=14.2, 15.4, 23.0, 27.3, 28.4,
56.5, 61.0, 61.9, 71.5 (alkyne-C), 78.9 (alkyne-C), 102.6
(O2CH), 170.2 (CO2). IR (cm−1, film): wmax 2129, 1727.
HRMS: m/z: Found: 351.1775. Calc. for C17H28NaO6
[M++Na]: 351.1784.
1
liquid. H-NMR (400 MHz, CDCl3): l=0.93 (3H, t,
J=7.7 Hz, CH3), 1.40 (2H, m, CH2), 1.59 (2H, m,
CH2), 2.66 (2H, t, J=7.4 Hz, CH2S), 3.28 (2H, s,
SCH2CO2), 4.64 (1H, dd, J=6.3 1.8 Hz, ꢂCH2), 4.95
(1H, dd, J=14.0, 1.8 Hz, ꢂCH2), 7.29 (1H, dd, J=
14.0, 6.3 Hz, CHꢂ). 13C-NMR (100 MHz, CDCl3):
l=14.1 (CH3), 22.3 (CH2), 31.5 (CH2), 32.9 (CH2S),
33.8 (SCH2CO2), 99.0 (ꢂCH2), 141.8 (CHꢂ), 168.0
(CO2). IR (cm−1, film): wmax 3093, 2059, 2882, 1759,

116
W.J. Kerr et al. / Journal of Organometallic Chemistry 630 (2001) 104–117
4.17. Diethyl hept-6-yn-1-al-4,4-dicarboxylate (18)
CH2Cl2 (40 ml) was added to a stirred solution of
octacarbonyldicobalt (1.34 g, 3.93 mmol) in CH2Cl2 (40
ml) at 25 °C. The mixture was stirred for 1 h before it
was filtered through a pad of silica using a light
petroleum eluent to remove less polar impurities, then
10% Et2O in light petroleum to elute hexacarbonyl[m-
[(6,7-p:6,7-p)-(E/Z)-diethyl 1-acetoxyhept-1-en-6-yne-
4,4-dicarboxylate]]dicobalt-(CoꢁCo) (19) (2.17 g, 95%)
as a red oil. Anal. Found: C, 43.0; H, 3.4. Calc. for
Diethyl 7,7-diethoxyhept-1-yne-4,4-dicarboxylate (17)
(1.89 g, 5.76 mmol) was added to dilute aqueous HCl
solution (1 M, 70 ml) and the mixture was heated on a
steam bath for 30 min. The mixture was then extracted
with Et2O (3×50 ml) and the combined extracts were
dried and evaporated under reduced pressure to give
diethyl hept-6-yn-1-al-4,4-dicarboxylate (18) (1.44 g,
99%) as a pale yellow oil. 1H-NMR (400 MHz, CDCl3):
l=1.26 (6H, t, J=7.2 Hz, CH3), 2.03 (1H, t, J=2.7
Hz, HCꢀ), 2.38 (2H, m, H-3), 2.51 (2H, m, H-2), 2.81
(2H, d, J=2.7 Hz, H-5), 4.20 (4H, m, 2×OCH2), 9.74
(1H, s, HCO). 13C-NMR (100 MHz, CDCl3): l=14.2,
23.7, 24.9, 39.2, 56.0, 62.1 (OCH2), 72.0 (alkyne-C),
1
C21H20Co2O12 requires C, 43.3; H, 3.4%. H-NMR (400
MHz, CDCl3): l=1.29 (6H, t, J=6.8 Hz, 2×
CH3CH2), 2.10, 2.18 (3H, 2×s, CH3CO), 2.71, 2.90
(2H, 2×d, J=8.1, 7.3 Hz, H-3), 3.62, 3.64 (2H, 2×s,
H-5), 4.22 (4H, m, 2×OCH2), 4.79, 5.30 (1H, 2×m,
H-2), 5.98, 5.99 (1H, 2×s, HCꢀ), 7.15 (1H, 2×over-
lapping d, H-1). 13C-NMR (100 MHz, CDCl3): l=
14.2, 20.8, 20.9, 28.2, 30.8, 37.7, 38.0, 57.9, 58.7, 61.9,
62.0, 73.4, 87.3 (107.0 and 108.0 (C-2)), (137.0 and
138.5 (C-1)), 168.0 (CO2CH2), (170.0 and 170.3
(CH3CO2)), 199.7 (CO). IR (cm−1, film): wmax 2097,
2053, 2002, 1740, 1638.
78.6 (alkyne-C), 169.9 (CO2), 200.7 (HCO). IR (cm−1
film): wmax 2985, 2940, 2927, 2908, 1733. HRMS: m/z:
Found: 255.1234. Calc. for C13H19O5 [M++1]:
255.1232.
,
4.18. (E/Z)-Diethyl 1-acetoxyhept-1-
en-6-yne-4,4-dicarboxylate (15)
Potassium carbonate (42.0 mg, 0.30 mmol) was
added to a solution of diethyl hept-6-yn-1-al-4,4-dicar-
boxylate (18) (0.78 g, 3.07 mmol) in Ac2O (30 ml) and
the mixture was heated under reflux for 2 h. The
mixture was then concentrated under reduced pressure
and the residue was partitioned between Et2O (50 ml)
and saturated aqueous sodium hydrogen carbonate so-
lution (50 ml). The organic phase was dried and evapo-
rated under reduced pressure to leave a crude residue,
which was purified by column chromatography on sil-
ica using 50% Et2O in light petroleum as the eluent to
give diethyl 1-acetoxyhept-1-en-6-yne-4,4-dicarboxylate
(15) (0.70 g, 77%) as a colourless oil containing both E-
4.20. Diethyl 3,3a,4,5-tetrahydro-5-oxo-(1H)-
pentalene-2,2-dicarboxylate (20) [33]
A solution of N-methylmorpholine N-oxide monohy-
drate (1.00 g, 7.40 mmol) in CH2Cl2 (25 ml) was added
over a 90 min period (syringe pump) to a stirred
solution of hexacarbonyl[m-[(6,7-h:6,7-h)-(E/Z)-diethyl
1-acetoxyhept-1-en-6-yne-4,4-dicarboxylate]]dicobalt-
(CoꢁCo) (19) (0.43 g, 0.74 mmol) in CH2Cl2 (15 ml) at
25 °C. The mixture was stirred for 16 h before it was
filtered through a pad of silica using Et2O as the eluent.
The filtrate was evaporated under reduced pressure to
leave a crude residue which was purified by column
chromatography on silica using a 20–50% Et2O in light
petroleum gradient as the eluent to give diethyl
3,3a,4,5-tetrahydro-5-oxo-(1H)-pentalene-2,2-dicarb-
1
and Z-isomers. H-NMR (400 MHz, CDCl3): l=1.34
(6H, t, J=7.1 Hz, 2×CH3CH2), 2.09, 2.12 (1H, 2×t,
J=2.7 Hz, HCꢀ), 2.18, 2.23 (3H, 2×s, CH3CO), 2.84,
3.01 (2H, 2×dd, J=8.2, 1.2, 7.8, 1.4 Hz, H-3), 2.87
(2H, d, J=2.7 Hz, H-5), 4.30 (4H, m, 2×OCH2), 4.82,
5.34 (1H, 2×m, 2-H), 7.21, 7.25 (1H, 2×d, J=6.5,
12.3 Hz, H-1). 13C-NMR (100 MHz, CDCl3): l (14.2
and 20.8), (22.8 and 23.0), (27.6 and 30.3), (56.7 and
57.0), (61.9 and 62.0 (OCH2)), (71.3 and 71.9 (alkyne-
C)), (78.8 and 79.2 (alkyne-C)), (107.2 and 108.0 (C-2)),
(137.4 and 138.7 (C-1)), 167.0 (CO2CH2) and (169.7
and 169.8 (CH3CO2)). IR (cm−1, film): wmax 2104, 1753,
1734, 1676. HRMS: m/z: Found: 297.13186. Calc. for
C15H21O6 [M++1]: 297.13381.
1
oxylate (20) (10 mg, 54%) as a colourless oil. H-NMR
(400 MHz, CDCl3): l=1.21 (6H, apparent q, J=7.3
Hz, CH3), 1.70 (1H, app. t, J=12.7 Hz), 2.09 (1H, dd,
J=17.8, 3.2 Hz), 2.59 (1H, dd, J=17.9, 6.4 Hz), 2.76
(1H, dd, J=12.7, 7.6 Hz), 3.07 (1H, m), 3.26 (2H, m),
4.19 (4H, m, 2×OCH2), 5.89 (1H, m, H-6). IR (cm−1
film): wmax 3080, 2939, 1731, 1709, 1636.
,
Acknowledgements
4.19. Hexacarbonyl[v-[(6,7-p:6,7-p)-(E/Z)-diethyl
1-acetoxyhept-1-en-6-yne-4,4-dicarboxylate]]-
dicobalt-(CoꢁCo) (19)
We are grateful to the Carnegie Trust for the Univer-
sities of Scotland for the award of a postgraduate
scholarship to M.M. We also wish to thank Pfizer
Global Research and Development, Sandwich for gen-
erous funding of our research endeavours and the
A solution of (E/Z)-diethyl 1-acetoxyhept-1-en-6-
yne-4,4-dicarboxylate (15) (1.16 g, 3.93 mmol) in

W.J. Kerr et al. / Journal of Organometallic Chemistry 630 (2001) 104–117
117
(d) H.J. Bestmann, H. Frey, Justus Liebigs, Ann. Chem. (1980)
2061.
[14] C.M. de Oliveira, V.L. Ferracini, M.A. Foglio, A. de Meijere,
A.J. Marsaioli, Tetrahedron: Asymmetry 8 (1997) 1833.
[15] C. Johnstone, W.J. Kerr, J.S. Scott, Chem. Commun. (1996)
341.
EPSRC Mass Spectrometry Service, University of
Wales, Swansea for analyses. We are also grateful to
Drs D.C. Billington and C.F. Farnocchi and Mr A.S.
Nicol for preliminary work.
[16] (a) M.E. Krafft, J. Am. Chem. Soc. 110 (1988) 968;
(b) M.E. Krafft, C.A. Juliano, I.L. Scott, C. Wright, M.D.
McEachin, J. Am. Chem. Soc. 113 (1991) 1693;
(c) M.E. Krafft, C.A. Juliano, J. Org. Chem. 57 (1992) 5106.
[17] (a) D.T. Warner, O.A. Moe, J. Am. Chem. Soc. 70 (1948) 3470;
(b) C.S. Marvel, H.W. Hill, J. Am. Chem. Soc. 73 (1951) 481.
[18] J.A. Soderquist, C.L. Anderson, Tetrahedron Lett. 27 (1986)
3961.
[19] A. Pictet, G. Jenny, Chem. Ber. 40 (1907) 1172.
[20] (a) Y. Iwashita, F. Tamura, A. Nakamura, Inorg. Chem. 8
(1969) 1179;
(b) Y. Iwashita, A. Ishikawa, M. Kainosho, Spectrochim. Acta,
Part A 27 (1971) 271.
[21] R.E. Connor, K.M. Nicholas, J. Organomet. Chem. 125 (1977)
C45.
[22] A.M. Hay, W.J. Kerr, G.G. Kirk, D. Middlemiss, Organometal-
lics 14 (1995) 4986.
[23] H. Greenfield, H.W. Sternberg, R.A. Friedel, J.H. Wotiz, R.
Markby, I. Wender, J. Am. Chem. Soc. 78 (1956) 120.
[24] Y.K. Chung, B.Y. Lee, N. Jeong, M. Hudecek, P.L. Pauson,
Organometallics 12 (1993) 220.
[25] C.H. DePuy, R.D. Thurn, M. Isaks, J. Org. Chem. 27 (1962)
744.
[26] Y. Amiel, A. Lo¨ffler, D. Ginsburg, J. Am. Chem. Soc. 76 (1954)
3625.
[27] S. Girard, P. Deslongchamps, Can. J. Chem. 70 (1992) 1265.
[28] A.B. Smith III, S.J. Branca, N.N. Pilla, M.A. Guaciaro, J. Org.
Chem. 47 (1982) 1855.
[29] E. Doris, L. Dechoux, C. Mioskowski, J. Am. Chem. Soc. 117
(1995) 12700.
References
[1] M.C. Croudace, N.E. Schore, J. Org. Chem. 46 (1981) 5357.
[2] C.F. Farnocchi, PhD thesis, University of Strathclyde, 1987.
[3] W.J. Kerr, M. McLaughlin, P.L. Pauson, S.M. Robertson,
Chem. Commun. (1999) 2171.
[4] I.U. Khand, P.L. Pauson, J. Chem. Res. (1977) (S)9, (M)168.
[5] A.R. Gordon, C. Johnstone, W.J. Kerr, Synlett (1995) 1083.
[6] (a) J.G. Donkervoort, A.R. Gordon, C. Johnstone, W.J. Kerr,
U. Lange, Tetrahedron 52 (1996) 7391;
(b) C. Johnstone, W.J. Kerr, U. Lange, J. Chem. Soc., Chem.
Commun. (1995) 457.
[7] S. Shambayati, W.E. Crowe, S.L. Schreiber, Tetrahedron Lett.
31 (1990) 5289.
[8] N. Jeong, Y.K. Chung, B.Y. Lee, S.H. Lee, S.-E. Yoo, Synlett
(1991) 204.
[9] T. Sugihara, M. Yamada, M. Yamaguchi, M. Nishizawa, Synlett
(1999) 771.
[10] J.G. Ford, W.J. Kerr, G.G. Kirk, D.M. Lindsay, D. Middlemiss,
Synlett (2000) 1415.
[11] (a) K.M. Brummond, J.L. Kent, Tetrahedron 56 (2000) 3263;
(b) Y.K. Chung, Coord. Chem. Rev. 188 (1999) 297;
(c) O. Geis, H.-G. Schmalz, Angew. Chem. Int. Ed. Engl. 37
(1998) 911;
(d) N.E. Schore, Org. React. 40 (1991) 1;
(e) N.E. Schore, in: B.M. Trost (Ed.), Comprehensive Organic
Synthesis, vol. 5, Pergamon Press, Oxford, 1991, p. 1037.
[12] (a) S. Ohira, Synth. Commun. 19 (1989) 561;
(b) S. Mu¨ller, B. Liepold, G.J. Roth, H.J. Bestmann, Synlett
(1996) 521.
[30] A. Scettri, G. Piancatelli, M. D’Auria, G. David, Tetrahedron 35
(1979) 135.
[13] (a) F. Ramirez, N.B. Desai, N. McKelvie, J. Am. Chem. Soc. 84
(1962) 1745;
[31] Y. Uyeda, E.E. Reid, J. Am. Chem. Soc. 42 (1920) 2385.
[32] D. Swern, E.F. Jordan, Org. Synth. Coll. Vol. IV (1963) 977.
[33] B.L. Pagenkopf, T. Livinghouse, J. Am. Chem. Soc. 118 (1996)
2285.
(b) E.J. Corey, P.L. Fuchs, Tetrahedron Lett. (1972) 3769;
(c) H.J. Bestmann, K. Li, Chem. Ber. 115 (1982) 828;
.