Stereoselective synthesis of (Z)-α-(alkoxycarbonyl)methylene β- and γ-lactones by palladium-catalysed oxidative carbonylation of alkynols

Article abstract of DOI:10.1039/a603892a

(Z)-α-(Alkoxycarbonyl)methylene β- and γ-lactones can be obtained in fair to excellent yields and with high catalytic efficiencies by PdI₂/KI-catalysed oxidative dialkoxycarbonylation of propynyl alcohols (α,α-dialkyl substituted, or α-monoalky

Full text of DOI:10.1039/a603892a

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Stereoselective synthesis of (Z )-á-(alkoxycarbonyl)methylene â- and
ã-lactones by palladium-catalysed oxidative carbonylation of alkynols
a
a
a
b
Bartolo Gabriele, Giuseppe Salerno, Francesca De Pascali, Mirco Costa
b
and Gian Paolo Chiusoli
a
Dipartimento di Chimica, Università della Calabria, 87030 Arcavacata di Rende, Cosenza,
Italy
b
Dipartimento di Chimica Organica e Industriale, Università di Parma, Viale delle Scienze,
3100 Parma, Italy
4
(
Z )-á-(Alkoxycarbonyl)methylene â- and ã-lactones can be obtained in fair to excellent yields and with
high catalytic efficiencies by PdI /K I-catalysed oxidative dialkoxycarbonylation of propynyl alcohols
2
(á,á-dialkyl substituted, or á-monoalkyl substituted with a sufficiently bulky alkyl group) and but-3-yn-1-
ols, respectively. Reactions are carried out in alcoholic media under mild conditions (70–80 ЊC and 20 atm
of a 3 :1 mixture of carbon monoxide and air). Reaction pathways are discussed.
Introduction
Transition metal-catalysed carbonylation of alkynols is an
attractive route to α-methylene lactone derivatives. The α-
methylene lactone unit occurs in some natural products, which
1
show a wide spectrum of physiological activity. A palladium-
catalysed synthesis of α-methylene γ-lactones was achieved by
2
additive monocarbonylation of but-3-yn-1-ols. More recently,
palladium-catalysed oxidative monocarbonylation of but-3-yn-
1
-ols to α-methoxymethylene γ-lactone derivatives was also
reported, while catalytic oxidative dicarbonylation to α-(meth-
oxycarbonyl)methylene γ-lactones was obtained only in the
3
case of 4-(trimethylsilyl)but-3-yn-1-ols. β-Lactones were not
formed by analogous carbonylations of propynyl alcohols,
4
however. α-(Triorganosilyl)methylene β-lactones were ob-
5
tained by rhodium-catalysed silylcarbonylation of alkynols.
We now report the synthesis of (Z)-α-(alkoxycarbonyl)-
methylene β- and γ-lactones by palladium-catalysed oxidative
dicarbonylation of propynyl alcohols (α-alkyl substituted) and
but-3-yn-1-ols, respectively. A preliminary account, limited to
6
α,α-disubstituted propynyl alcohols, was published recently.
Results and discussion
Earlier we described a new and efficient method for the oxid-
7
ative carbonylation of alk-1-ynes to maleic diesters. The reac-
tions were carried out in alcoholic media at 25–60 ЊC and 20 atm
of a CO–air mixture (3:1) in the presence of catalytic amounts
of PdI + 10 KI [eqn. (1)].
2
is in agreement with the syn character of the carbon monoxide
insertion reaction.
8
,9
The main by-products are maleic diesters 3, acetylenic esters
4
(corresponding to oxidative monocarbonylation) and prod-
ucts 5 derived from ring opening of 2 by alcohol attack at C-4.
1
d
The latter reaction is characteristic of the β-lactone unit. It
has been ascertained that the isolated β-lactones 2 are slowly
converted into 5 when heated in alcoholic media at 80 ЊC. For
example, 2a was partly converted into 5a (7%) when treated with
methanol at 80 ЊC for 6 h. Small amounts of products 6 (cyclic
7
tautomeric form of 3), 7, 8 and 9 were detected in the reaction
If the method is applied to substituted propynyl alcohols
mixtures deriving from 1a and 1c. Compound 7 originates from
etherification of the alcoholic function of 3 (a reaction which
also occurs with simple propynyl alcohol), while 8 corresponds
to ring opening of 2 by attack at C-4 by the reaction with water.
Formation of 9 implies a β-hydroxy elimination from the
(
α,α-dialkyl substituted, or α-monoalkyl substituted with a suf-
ficiently bulky alkyl group), β-lactone derivatives with (Z )-α-
alkoxycarbonyl)methylene chains are formed as the main
products, according to eqn. (2). The stereoselectivity observed
7
(
J. Chem. Soc., Perkin Trans. 1, 1997
147

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Table 1 Reactions of α-substituted propynyl alcohols with CO–air (3:1) and MeOH at 80 ЊC, initial pressure 20 atm at 20 ЊC, PdI –KI molar ratio
2
Ϫ3
1
:10, substrate conc./mol dm (in MeOH):0.22
Substrat-
Substrate:catalyst
Conv’n
(%)
Yield of 2
(%)
Total
yield (%)
a
a
a
Run
Substrate
t/h
Product :catalyst
b
1
2
3
4
5
6
7
8
9
1a
1a
1a
1b
1b
1c
1c
1d
1d
500
2000
2000
100
1000
100
1000
500
2000
3
6
15
5
6
5
8
4
6
95
73
53
90
70
80
64
84
72
80
54
45
76
56
57
41
52
31
95c
475
1420
1060
86
700
78
620
405
1360
71e
53
d
f
86
70
g
h
78i
62
81
68
j
k
a
d
h
b
c
Based on starting propynyl alcohol, by GLC. Including 3a (10%), 5a (1%), 6a (3%) and 7a (1%). Including 3a (12%), 5a (2%) and 6a (3%).
e
f
g
Reaction carried out at 60 ЊC. Including 3a (6%) and 6a (2%). Including 3b (6%), 4b (1%) and 5b (3%). Including 3b (6%), 4b (3%) and 5b (5%).
Including 3c (4%), 4c (4%), 5c (2%), 8c (8%) and 9c (3%). including 3c (6%), 4c (3%), 5c (4%), 8c (6%) and 9c (2%). Including 3d (26%) and 4d
i
j
k
(
3%). Including 3d (33%) and 4d (4%).
of 1a, 1420 mol of carbonylated products per mol of palladium
used could be obtained after 6 h (run 2), while 700 and 620 mol
of products per mol of catalyst were obtained using 1b (run 5)
and 1c (run 7) after 6 and 8 h, respectively.
The presence of alkyl substituents α to the triple bond is
essential in order to achieve good selectivities for β-lactones.
Product distribution deriving from unsubstituted propynyl
alcohol is similar to that of simple alkyl- or aryl-acetylenes, the
corresponding maleic diester and its cyclic isomer being the
main products of the reaction with no formation of the β-
7
lactone derivative. On the other hand, yields of β-lactones
deriving from α-monoalkylsubstituted propynyl alcohols
are very low if the alkyl group is not sterically demanding.
Thus, but-3-yn-2-ol 1f, when allowed to react in methanol
for 2 h under the usual conditions (substrate:catalyst = 2000),
yielded only 2% of the corresponding β-lactone 2f at 80% con-
version. Maleic diester 3f (50%), its cyclic tautomer 6f (9%), the
fumaric derivative 10f (12%) and γ-lactone 11f (6%) accounted
for the converted substrate [eqn. (3)].
initially formed (alkoxycarbonyl)vinylpalladium complex re-
sulting from alkoxycarbonylation of 1.
Table 1 reports the results obtained with different substituted
propynyl alcohols at 80 ЊC in methanol as the solvent, using
substrate:catalyst ratios of 100–2000. The reaction took place
even at 60 ЊC, although the reaction rate was decreased, as
shown by comparison between run 2 and run 3.
Reactions can also be effected using higher alcohols as the
solvent. Under conditions similar to those of run 1, but using a
substrate/Pd molar ratio = 100, the reaction of 1a in butan-1-ol
proceeded more slowly, giving 75% conversion in 5 h, with 44%
yield of 2e, 22% of 3e, 2% of 6e and 3% of 7e.
Product 10f derives from etherification of the alcoholic func-
tion of 3f with double bond isomerization, while the presence
of small amounts of 11f implies Z to E isomerization of a
carbonylated species which must occur within a palladium-
bonded intermediate, since Z to E isomerization of the maleic
7
derivatives does not readily occur under our conditions.
Although the reactions were carried out in alcohols at 80 ЊC,
selectivities for β-lactones 2 were rather good, ranging from 43
to 85%. Reaction times longer than those reported resulted in
lower selectivities for 2, although the total yields were higher.
Substrate reactivity tends to be lower when steric hindrance
exerted by alkyl substituents increases. For example, in the case
γ-Lactones with (Z )-α-(alkoxycarbonyl)methylene chains
were obtained by PdI /KI-catalysed oxidative dialkoxycar-
2
bonylation of but-3-yn-1-ols 12 [eqn. (4)].
Table 2 reports the results obtained with different butynols
using methanol as the solvent, with a substrate:catalyst molar
ratio of 500. Reactions were carried out at 70 rather than 80 ЊC
1
48
J. Chem. Soc., Perkin Trans. 1, 1997

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Table 2 Reactions of but-3-yn-1-ols with CO–air (3:1) and MeOH at 70 ЊC, initial pressure 20 atm at 20 ЊC, PdI –KI molar ratio 1:10, substrate–Pd
2
Ϫ3
molar ratio 1:500, substrate conc./mol dm (in MeOH): 0.22
Conv’n
(%)
Yield of 13
(%)
Total
yield (%)
a
a
a
Run
Substrate
t/h
Product :catalyst
b
1
1
1
1
1
0
1
2
3
4
12g
12h
12i
12j
12k
12
12
24
15
15
99
98
92
100
100
86
94
73
93
28
99c
495
490
460
465
470
98
d
e
92
93
94
f
f
g
a
e
b
c
d
Based on starting but-3-yn-1-ol, by GLC (unless otherwise noted). Including 14g (13%). Including 14h (4%). Reaction carried out at 80 ЊC.
f
g
Including 15i (19%). Isolated yield. Including 14k (62%) and 16k (4%).
3
7,10
starting from the alcoholic solvent R OH; in this case, two
different directions of attack on the triple bond are possible
(
path a and b, respectively); (b) starting from the alcoholic func-
8
tion of the substrate (path c).
In the case of intermediate I, intramolecular attack by the
hydroxy group on the acylpalladium moiety would readily
explain lactone formation, while intermolecular attack by
3
R OH would account for the maleic diester formation (Scheme
2
). On the other hand, the acylpalladium moiety of the regio-
isomeric intermediate II can only undergo intermolecular
attack by R OH to give the maleic diester [eqn. (5)], the intra-
in order to maximize the selectivity in γ-lactones 13, except for
less reactive substrates such as 2,2-dimethylbut-3-yn-1-ol (12i,
run 12).
3
In contrast to the propynyl alcohols, substitution α to the
triple bond of but-3-yn-1-ols is not necessary in order to direct
the carbonylation process towards ring closure to give γ-lactones
selectively. But-3-yn-1-ol 12g, pent-4-yn-2-ol 12h and cis-2-
ethynylcyclopentan-1-ol 12j were, in fact, converted into their
corresponding γ-lactones 13g, 13h and 13j in excellent yields
molecular attack by the hydroxy group being impossible for
geometric reasons. Lactone formation, however, is compatible
with path b as well, since in this case an intramolecular ester
exchange reaction becomes possible with formation of inter-
mediate III, from which the final ester lactone is obtained by
(runs 10, 11 and 13, respectively). Maleic diesters 14g and 14h
were formed as by-products in the reactions of compounds 12g
and 12h. Where there was dialkyl substitution α to the triple
bond as in 12i, the reaction was slower, and the product yield of
the γ-lactone 13i lower, with the acetylenic ester 15i being ob-
tained as a by-product (run 12). When cyclization is disfavoured
by molecular geometry, as in the case of trans-2-ethynylcyclo-
pentan-1-ol 12k, product distribution changes in favour of
maleate, the γ-lactone being obtained as a by-product (run 14).
3
R OH attack on the acylpalladium bond [eqn. (6)]. Also, the
maleic diester could lactonize according to eqn. (7). As
7
,8,10
According to what has been previously reported,
the car-
bonylation process should be initiated by syn addition of an
alkoxycarbonylpalladium species to the triple bond followed by
carbon monoxide insertion to give an acylpalladium intermedi-
ate (Scheme 1; anionic iodide ligands are omitted for sim-
plicity). The acylpalladium intermediate can be formed (a)
depicted in Scheme 1, intermediate III can be formed directly
by path c, without passing through path b.
J. Chem. Soc., Perkin Trans. 1, 1997
149

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Scheme 1
alkyl group is clearly caused by the steric effect exerted by the
alkyl groups α to the triple bond, which favours the bonding
between the alkoxycarbonyl group and the less congested ter-
minal carbon. A similar effect was observed by Nogi and Tsuji
in the PdCl -catalysed carbonylation of prop-2-yn-1-ol and 2-
2
4
a
methylbut-3-yn-2-ol in methanol as the solvent. In the pres-
ence of geminal alkyl groups, as in 1a–c, ring formation at the
acylpalladium intermediate level is favoured in respect to car-
1
1
bonyl esterification by the gem-dialkyl effect. This allows for-
mation of β-lactones to a substantial extent even in the pres-
ence of an alcohol as the solvent. The lower β-lactone:maleate
ratio obtained in the case of 1d is reasonable, since the
gem-dialkyl effect is not at work when only one alkyl group α to
the triple bond is present, and therefore the intermolecular
Scheme 2
Which of these pathways is the main reaction route appears
to be dependent on the nature of the starting alkynol.
In respect of propynyl alcohols, although path c would read-
ily explain β-lactone formation, it does not explain the experi-
mental result that β-lactones are formed as the main products
only when α,α-dialkyl substitution (or monoalkyl substitution,
with the alkyl group sufficiently bulky) is present on the triple
bond. On the other hand, the isolated maleic diesters 3 are not
converted into the corresponding β-lactones 2 under the reac-
tion conditions, which means that an intramolecular ester
exchange reaction is not at work. Consequently, β-lactones are
not formed by path b, which is the route normally followed
under our conditions by arylacetylenes and alkylacetylenes
with no substituents α to the triple bond (including propynyl
3
attack by R OH becomes more competitive in respect to the
intramolecular attack by the hydroxy group.
Alkyl substitution α to the triple bond slows down the carbon
monoxide insertion into the palladium–vinyl bond, so the
vinylpalladium intermediate can undergo side reactions such as
β-hydrogen elimination and/or HI-promoted allenic rearrange-
ment. This explains the formation of by-products 4 [eqn. (8),
1
2
1
2
3
R = CR R OH] and 9c [eqn. (9), R ᎐R = (CH
)
, R = Me].
2
5
7
alcohol). Therefore, experimental results strongly suggest
path a as the main reaction route. This is also supported by
the formation of by-products 4, which necessarily derive from
path a [eqn. (8), R = CR R OH].
1
2
In the case of butynols 12g and 12h, path a should not be at
work, since there are no substituents α to the triple bond and,
therefore, the initial addition of the alkoxycarbonyl group
occurs on the internal carbon of the triple bond ultimately
leading to maleic diesters 14g and 14h (path b). To ascertain
whether the latter could be converted into γ-lactones 13g and
1
3h we followed their behaviour under the reaction conditions
The small amounts (2–3%) of products 6 are formed by the
less favoured path b (Scheme 3).
without noticing lactonization. Thus, γ-lactones 13g and 13h
must be formed by path c. This pathway could be favoured in
respect to path b, even in an alcoholic solvent, due to the form-
ation of a particularly stable five-membered chelate alkoxy-
7
3
palladium complex IV.
Scheme 3
Inversion of the regiochemistry of insertion of the triple
3
bond into the Pd᎐CO R bond when the triple bond is α.α-
On the other hand, the small amounts of maleic diesters 14g
and 14h must be formed by path b, since the isolated γ-
2
dialkyl substituted or α-monoalkyl substituted with a bulky
1
50
J. Chem. Soc., Perkin Trans. 1, 1997

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lactones 13g and 13h are not converted into 14g and 14h
under the described reaction conditions.
times, temperature, substrate concentration and substrate to
catalyst ratios used are indicated in Tables 1 and 2.
Path a is at work when the butynol is α,α-dialkyl substituted,
as in 12i, as suggested by the formation as a by-product of the
acetylenic ester 15i [eqn. (8), R = CMe CH OH]. Both path c
and path a may account for γ-lactone formation in this case.
In conclusion, α-substituted propynyl alcohols and but-3-yn-
Separation of products
Compounds 2a, 3a + 6a and 5a were eluted in this order by
chromatography through a SiO column, using a concentration
gradient of hexane–ethyl acetate from 90:10 to 0:100. Products
2
2
2
1
-ols can efficiently undergo, under mild conditions, oxidative
3a and 6a were subsequently separated by column chrom-
dialkoxycarbonylation to (Z)-α-(alkoxycarbonyl)methylene β-
or γ-lactones respectively with good selectivity and high cata-
lytic efficiency, in the presence of a catalytic system based on
atography (SiO ) using a mixture of light petroleum (bp 40–
2
70 ЊC)–acetone (95:5) as eluent. Pure compound 7a was
obtained from an experiment similar to run 2 but carried out
for 15 h. Chromatographic separation was effected on the crude
2
Ϫ
the PdI4 anion.
reaction mixture on a SiO column (hexane–ethyl acetate from
2
9
7
0:10 to 0:100; order of elution: 7a, 2a, 3a + 6a, 5a). Products
e, 2e, 6e (in a mixture with 2e), 3e and 5e were eluted in this
Experimental
Mps were determined on a Reichert Thermovar melting point
apparatus and are uncorrected. Elemental analyses were carried
out with a Carlo Erba Elemental Analyser Mod. 1106. IR Spec-
tra were recorded on a Perkin-Elmer Paragon 1000 PC FT-IR
spectrometer. Mass spectra were obtained using an HP 5972A
order by chromatography through a SiO column, using a con-
2
centration gradient of hexane–acetone from 98:2 to 0:100.
Product 6e was subsequently separated from 2e by PTLC (SiO2)
using hexane–acetone (90:10) as eluent. Products 4b, 2b, 3b
and 5b; 9c, 4c, 2c, 3c, 5c and 8c; 4d, 2d and 3d; 10f, 11f, 2f, 3f
and 6f (in a mixture with 3f) were eluted in the order as above
using a concentration gradient of hexane–ethyl acetate from
1
spectrometer at 70 eV ionizing voltage. H NMR Spectra were
taken on a Bruker AC300 spectrometer and run on CDCl3
1
solutions with Me Si as internal standard. Chemical shifts
90:10 to 0:100. Product 6f was identified by mass, IR and H
4
and coupling constants (J) are given as δ values (ppm) and in
Hz, respectively.
NMR spectroscopy directly in the mixture with 3f.
Compounds 13g and 14g were eluted in this order by chrom-
atography through a SiO2 column, using a concentration
gradient of chloroform–acetone from 100:0 to 98:2. Products
13h and 14h were separated in a similar way. Product 13j was
The reaction mixtures were analysed by TLC (SiO or Al O )
2
2
3
or by GLC using capillary columns with polymethylsili-
cone + 5% phenylsilicone (HP-5) or TPA-modified polyethyl-
eneglycol (HP-FFAP) as the stationary phase. Quantitative
determination of the products was carried out by GLC using
the internal standard method. Products were separated by con-
ventional extraction techniques, followed by chromatographic
procedures on silica or allumina with suitable eluents. Merck
silica gel 60 (60–230 mesh) and neutral allumina 90 (70–230
mesh) were used for column chromatography. Analytical TLC
plates and silica gel 60F254 for PTLC were purchased from
Merck.
purified through a SiO column, using chloroform as eluent.
2
Products 16k, 13k and 14k and 15i and 13i were eluted in the
order as above using chloroform as eluent.
Characterization of products
Identification of known products 7a and 9c was carried out
4
a
14
by comparison with literature data. New compounds were iden-
1
tified by elemental analysis and IR, H NMR and MS data.
4,4-Dimethyl-3-[(Z )-(methoxycarbonyl)methylene]-1-oxacy-
clobutan-2-one 2a. White solid, mp 79–80 ЊC (Found: C, 56.7;
Ϫ1
Preparation of alkynols
H, 6.0. C H O requires C, 56.5; H, 5.9%); νmax(KBr)/cm
8
10
4
Acetylenic alcohols 2-methylbut-3-yn-2-ol 1a, 3-methylpent-1-
yn-3-ol 1b, 1-ethynylcyclohexanol 1c, but-3-yn-2-ol 1f, but-3-
yn-1-ol 12g and pent-4-yn-2-ol 12h are commercial products
3078vw, 2996vw, 1808s, 1727s, 1690s, 1441w, 1384vw, 1370vw,
1291s, 1229vw, 1205m, 1082w, 1038m, 921w, 885vw, 820w and
786m; δ 1.67 (6 H, s, 2 Me), 3.85 (3 H, s, CO Me) and 5.92 (1
H, s, ᎐CH); m/z 170 (M , <0.5%), 155 (28), 141 (3), 126 (51),
125 (61), 113 (100), 112 (21), 111 (92), 98 (7), 95 (13), 85 (13), 83
(39), 82 (31), 73 (16), 69 (15), 67 (98), 65 (21), 59 (66) and 53
H
2
1
2
+
(
Aldrich, Fluka). 2,2-Dimethylbut-3-yn-1-ol 12i
cis-2-
2
a
ethynylcyclopentanol 12j and trans-2-ethynylcyclopentanol
2
a
1
2k were prepared according to literature procedures.
(80).
4
-Ethylhex-1-yn-3-ol 1d
4-Ethyl-3-[(Z )-(methoxycarbonyl)methylene]-4-methyl-1-
oxacyclobutan-2-one 2b. White solid, mp 34–35 ЊC (Found: C,
1
3
This alkynol, prepared by ethynylation of 2-ethylbutanal,
which is commercially available, was a colourless liquid, bp 72–
Ϫ1
58.6; H, 6.6, C H O requires C, 58.7; H, 6.5%); νmax(film)/cm
9
12
4
7
7
2
1
7
3 ЊC/15 mmHg (Found: C, 76.3; H, 11.0. C H O requires C,
2978m, 2955m, 2885w, 1817s, 1733s, 1694m, 1461m, 1437m,
1382w, 1338s, 1287s, 1162s, 1081s, 1018m, 901w, 882w, 823m
8
14
Ϫ1
6.2; H 11.1%); νmax(film)/cm 3380m br, 3309s, 2963s, 2934s,
877s, 2113w, 1462m, 1381m, 1330w, 1277w, 1247w, 1129w,
024m and 890w; δH 0.93 (3 H, t, J 7.25, Me), 0.94 (3 H, t, J
.32, Me), 1.30–1.68 (5 H, m, CH CHCH ), 2.45 (1 H, d, J 2.24,
and 785m; δ 1.04 (3 H, t, J 7.48, Me), 1.64 (3 H, s, Me), 1.95 (2
H
H, q, J 7.48, CH ), 3.84 (3 H, s, CO Me) and 5.97 (1 H, s, ᎐CH);
2
2
+
m/z 184 (M , <0.5%), 169 (2), 156 (9), 155 (100), 141 (2), 125
(65), 113 (99), 97 (7), 85 (5), 82 (11), 81 (28), 79 (16), 77 (5), 69
(6), 59 (18), 57 (16) and 53 (36).
2
2
C᎐CH) and 4.42 (1 H, dd, J 2.24 and 4.37, CHOH); m/z 126
᎐
+
(M , absent), 125 (<0.5%), 111 (4), 98 (6), 97 (16), 93 (8), 84
(27), 83 (22), 79 (8), 77 (12), 71 (41), 70 (39), 69 (20), 67 (8), 65
(4), 57 (16), 56 (51), 55 (100) and 53 (22).
3-[(Z )-(Methoxycarbonyl)methylene]-1-oxaspiro[3,5]nonan-2-
one 2c. White solid, mp 71–72 ЊC (Found: C, 63.0; H, 6.6.
Ϫ1
C H O requires C, 62.9; H, 6.7%); νmax(KBr)/cm 2940m,
1
1
14
4
General procedure for catalytic oxidative carbonylation of
alkynols
The carbonylations were carried out in a 300 cm stainless steel
2861w, 1807s, 1725s, 1690m, 1447m, 1294m, 1170w, 1033m,
903m and 790m; δH 1.37–2.07 (10 H, m, 5 CH ), 3.85 (3 H, s,
2
3
+
CO Me) and 6.00 (1 H, s, ᎐CH); m/z 210 (M , 1%), 195 (1), 178
2
autoclave (Parr) with magnetic stirring. In a typical experiment
(13) 168 (18), 165 (9), 155 (22), 154 (58), 151 (50), 150 (42), 140
(27), 137 (23), 126 (22), 123 (53), 122 (33), 113 (29), 107 (19),
105 (25), 99 (20), 95 (37), 94 (23), 91 (31), 82 (34), 81 (28), 80
(22), 79 (47), 77 (24), 69 (39), 67 (35), 65 (19), 59 (39), 55 (100)
and 53 (79).
the autoclave was charged in the presence of air with PdI , KI
2
(10 mol per mol of palladium) and the appropriate alkynol
dissolved in MeOH or BuOH. The autoclave was pressurized
with CO (15 atm) and air (up to 20 atm of total pressure) and
heated and stirred for the required time. Care must be taken to
fill the autoclave to levels that allow the presence of a sufficient
amount of oxygen necessary for the reoxidation cycle. Reaction
3-[(Z )-Methoxycarbonyl)methylene]-4-(pentan-3-yl)-1-oxa-
cyclobutan-2-one 2d. Colourless oil (Found: C, 62.5; H, 7.6.
Ϫ1
C H O requires C, 62.3; H, 7.5%); νmax(film)/cm 2965m,
1
1
16
4
J. Chem. Soc., Perkin Trans. 1, 1997
151

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2
1
940w, 2879w, 1825s, 1734s, 1695w, 1461w, 1437w, 1337m,
Colourless oil (Found: C, 62.8; H, 9.2. C H O requires C,
15 26 5
Ϫ1
287m, 1213m, 1118m, 1069m and 870m; δ 0.95 (3 H, t, J 7.48,
62.9; H, 9.1%); νmax(film)/cm
3496m br, 2961s, 2935m,
H
Me), 0.96 (3 H, t, J 7.48, Me), 1.35–1.59 (4 H, m, 2 CH ), 1.68–
2874w, 1720s, 1646m, 1465m, 1391m, 1339m, 1253s, 1173s,
2
1
6
2
9
.80 (1 H, m, CHEt ), 3.85 (3 H, s, CO Me), 4.94 (1 H, dd, J
1062m, 1042w, 962w, 890w and 735m; δH 0.93 (3 H, t, J 7.30,
2
2
.76 and 1.64, CHOC᎐O) and 6.04 (1 H, d, J 1.64, ᎐CH); m/z
Me), 0.95 (3 H, t, J 7.31, Me), 1.33–1.53 (4 H, m, 2 CH ), 1.47 (6
᎐
᎐
2
+
12 (M , <0.5%), 183 (2), 153 (2), 142 (52), 141 (10), 110 (100),
H, s, 2 Me), 1.53–1.76 (4 H, m, 2 CH ), 4.12 (2 H, t, J 6.70,
2
5 (2), 82 (9), 71 (11), 69 (5), 59 (13), 55 (12) and 53 (16).
3
CH OC᎐O), 4.25 (2 H, t, J 6.67, CH OC᎐O) and 6.10 (1 H, s
2
2
+
-[(Z )-(Butoxycarbonyl)methylene]-4,4-dimethyl-1-oxacyclo-
butan-2-one 2e. Colourless oil (Found: C, 62.4; H, 7.4. C H O
4
requires C, 62.3; H, 7.5%); νmax(film)/cm 2963m, 2935m,
᎐CH); m/z 286 (M , absent), 271 (8%), 243 (1), 229 (5), 213 (7),
197 (10), 169 (6), 157 (13), 141 (100), 139 (49), 124 (5), 113 (55),
111 (26), 99 (14), 83 (15), 69 (7), 59 (22), 57 (57) and 55 (10).
Dimethyl (Z )-2-(1-hydroxyethyl)but-2-enedioate 3f. Colour-
less oil (Found: C, 51.1; H, 6.5. C H O requires C, 51.1; H,
1
1
16
Ϫ1
2
1
7
1
875w, 1821s, 1730s, 1693m, 1461w, 1387w, 1374w, 1331m,
274s, 1173s, 1066s, 1026m, 1015m, 908w, 819w, 793m and
19w; δH 0.95 (3 H, t, J 7.36, Me), 1.35–1.52 (2 H, m, CH ),
8
12
5
Ϫ1
6.4%); νmax(film)/cm 3441m br, 2983w, 2956m, 1726s, 1654m,
1438m, 1358m, 1270s, 1203s, 1172s, 1080m, 1007w, 925w and
890w; δ 1.39 (3 H, d, J 6.57, Me), 3.75 (3 H, s, CO Me), 3.85 (3
2
.58–1.75 (2 H, m, CH ), 1.67 (6 H, s, 2 Me), 4.23 (2 H, t, J 6.69,
2
+
CH OC᎐O) and 5.93 (1 H, s, ᎐CH); m/z 212 (M , absent), 197
2
H
2
(
1
(
<0.5%), 157 (6), 155 (3), 141 (19), 140 (25), 139 (100), 126 (2),
13 (8), 112 (53), 111 (80), 99 (8), 97 (13), 83 (51), 69 (10), 67
34), 59 (14), 57 (52), 56 (21), 55 (19) and 53 (24).
-[(Z )-(Methoxycarbonyl)methylene]-4-methyl-1-oxacyclo-
butan-2-one 2f. Colourless oil (Found: C, 53.6; H, 5.2. C H O
H, s, CO Me), 4.59 (1 H, qd, J 6.57 and 1.50, CHOH) and 6.12
(1 H, d, J 1.50, ᎐CH); m/z 188 (M , absent), 173 (19%), 157 (17),
145 (22), 141 (78), 129 (12), 124 (19), 114 (19), 113 (100), 97 (32),
85 (24), 82 (19), 69 (19), 59 (40), 55 (22) and 53 (40).
2
+
3
Methyl 4-hydroxy-4-methylhex-2-ynoate 4b. Colourless oil
(Found: C, 61.5; H, 7.8. C H O requires C, 61.5; H, 7.7%);
7
8
4
Ϫ1
requires C, 53.8; H, 5.1%); νmax(film)/cm 2956w, 2918w, 1822s,
8
12
3
Ϫ1
1
1
6
733s, 1696w, 1438m, 1337m, 1291m, 1260m, 1218m, 1135m,
νmax(film)/cm
3421m br, 2977m, 2941m, 2884w, 2236m,
111m, 1077m, 1019m, 909s, 831w and 732s; δ 1.63 (3 H, d, J
1718s, 1457m, 1437m, 1373w, 1256s, 1164m, 1137w, 1035m,
H
.33, Me), 3.85 (3 H, s, CO Me), 5.13 (1 H, qd, J 6.33 and 1.62,
994w, 926m and 753m; δ 1.06 (3 H, t, J 7.46, Me), 1.53 (3 H, s,
2
H
+
CHOC᎐O) and 6.00 (1 H, d, J 1.62, ᎐CH); m/z 156 (M , 60%),
1
Me), 1.70–1.81 (2 H, m, CH ) and 3.79 (3 H, s, CO Me); m/z
2 2
+
᎐
᎐
41 (1), 128 (6), 125 (29), 124 (100), 113 (28), 97 (33), 96 (11), 85
156 (M , absent), 155 (<0.5%), 141 (12), 128 (7), 127 (100), 125
(9), 113 (8), 109 (12), 96 (11), 95 (61), 85 (24), 81 (8), 71 (6), 69
(9), 59 (4), 57 (8), 55 (7) and 53 (84).
(14), 82 (42), 69 (11), 59 (18), 55 (41), 54 (12) and 53 (19).
Dimethyl (Z )-2-(1-hydroxy-1-methylethyl)but-2-enedioate 3a.
Colourless oil (Found: C, 53.5; H, 7.0. C H O requires C, 53.5;
H, 6.9%); νmax(film)/cm 3492m br, 2983m, 2955m, 1725s,
Methyl 3-(1-hydroxycyclohexyl)prop-2-ynoate 4c. White
solid, mp 39–40 ЊC (Found: C, 66.0; H, 7.7. C H O requires
9
14
5
Ϫ1
10
14
3
Ϫ1
1
9
649m, 1437s, 1347s, 1260s, 1196s, 1170s, 1046m, 1020m, 970w,
08m, 889w and 823w; δH 1.46 (6 H, s, 2 Me), 3.73 (3 H, s,
C, 65.9; H, 7.7%); νmax(film)/cm 3265m br, 2937m, 2861w,
2237m, 1713s, 1451m, 1435m, 1285m, 1242s, 1074m, 1042m,
944w and 753w; δ 1.20–2.03 (10 H, m, 5 CH ) and 3.78 (3 H, s,
CO Me), 3.85 (3 H, s, CO Me) and 6.11 (1 H, s, ᎐CH); m/z 202
2
+
2
H
2
+
(
(
M , absent), 187 (14%) 171 (6), 159 (7), 155 (100), 153 (16), 143
3), 139 (5), 127 (53), 114 (13), 113 (65), 111 (11), 99 (5), 85 (12),
CO Me); m/z 182 (M , <0.5%), 167 (2), 151 (27), 150 (46), 139
2
(44), 135 (18), 126 (30), 122 (57), 121 (49), 111 (57), 108 (26),
107 (96), 98 (38), 95 (77), 94 (59), 82 (24), 81 (41), 80 (34), 79
(76), 77 (22), 69 (36), 67 (37), 66 (32), 59 (17), 55 (87) and 53
(100).
8
3 (6), 82 (8), 69 (8), 59 (41) and 53 (15).
Dimethyl (Z )-2-(1-hydroxy-1-methylpropyl)but-2-enedioate
b. Colourless oil (Found: C, 55.5; H, 7.4. C H O requires C,
5.6; H, 7.4%); νmax(film)/cm 3509m br, 2978m, 2954m,
884w, 1728s, 1647m, 1456m, 1437m, 1348m, 1259s, 1202s,
168s, 1063w, 1036m, 1014m, 928w, 910w, 887w and 736w; δH
.93 (3 H, t, J 7.43, Me), 1.42 (3 H, s, Me), 1.65–1.78 (2 H, m,
3
5
2
1
0
1
0
16
5
Ϫ1
Methyl 5-ethyl-4-hydroxyhept-2-ynoate 4d. Colourless oil
(Found: C, 65.1; H, 8.8. C H O requires C, 65.2; H, 8.7%);
1
0
16
3
Ϫ1
νmax(film)/cm 3426m br, 2963s, 2935s, 2878m, 2235m, 1720s,
1461m, 1436m, 1383w, 1255s, 1132w, 1053m, 1025m, 968w,
CH ), 3.74 (3 H, s, CO Me), 3.85 (3 H, s, CO Me) and 6.08 (1
907w and 753m; δ 0.93 (3 H, t J 7.32, Me), 0.94 (3 H, t, J 7.32,
2
2
+
2
H
H, s, ᎐CH); m/z 216 (M , absent), 201 (1%), 187 (10), 169 (10),
Me), 1.30–1.68 (5 H, m, CH CHCH ), 3.79 (3 H, s, CO Me)
2 2 2
+
᎐
1
67 (7), 156 (9), 155 (100), 141 (15), 127 (6), 125 (6), 124 (4), 114
and 4.54 (1 H, d, J 4.47, CHOH); m/z 184 (M , absent) 166
(<0.5%), 153 (4), 124 (1), 115 (6), 114 (100), 110 (2), 99 (5), 85
(3), 82 (14), 81 (7), 71 (6), 68 (5), 67 (4), 59 (3), 55 (12) and 53
(15).
(5), 113 (47), 97 (2), 85 (6), 82 (5), 73 (7), 69 (5), 59 (9), 57 (11),
5
5 (8) and 53 (11).
Dimethyl (Z )-2-(1-hydroxycyclohexyl)but-2-enedioate 3c.
White solid, mp 59–60 ЊC (Found: C, 59.4; H, 7.4. C H O
4-Methyl hydrogen (Z )-2-(1-methoxy-1-methylethyl)but-2-
enedioate 5a. Colourless oil (Found: C, 53.4; H, 7.0. C H O
requires C, 53.5, H, 6.9%); νmax(film)/cm 3600–2800m br,
1
2
18
5
Ϫ1
requires C, 59.5; H, 7.4%); νmax(KBr)/cm 3496m br, 2937m,
860w, 1727s, 1645w, 1436m, 1346m, 1258s, 1200m, 1166s, 989w
and 882w; δ 1.09–1.86 (10 H, m, 5 CH ), 3.73 (3 H, s, CO Me),
9
14
5
Ϫ1
2
2983m, 2950m, 1725s, 1642m, 1435m, 1380m, 1330m, 1173s
H
2
2
+
3
.85 (3 H, s, CO Me) and 6.12 (1 H, s, ᎐CH); m/z 242 (M ,
and 1069m; δ 1.42 (6 H, s, 2 Me), 3.23 (3 H, s, OMe), 3.83 (3
2
H
+
absent), 211 (9%), 210 (54), 193 (21), 183 (37), 182 (48), 178
55), 167 (40), 155 (25), 154 (93), 151 (62), 150 (56), 140 (51),
39 (19), 136 (19), 126 (24), 123 (41), 122 (30), 113 (31), 105
H, s, CO Me) and 6.02 (1 H, s, ᎐CH); m/z 202 (M , absent), 155
2
(
1
(78%), 140 (8), 112 (8), 111 (7), 100 (4), 83 (100), 73 (10), 67
(11), 59 (7) and 53 (10).
(
(
21), 98 (21), 95 (32), 94 (21), 82 (29), 81 (49), 79 (21), 69 (38), 68
25), 67 (22), 59 (46), 55 (100) and 53 (57).
Dimethyl (Z )-2-(2-ethyl-1-hydroxybutyl)but-2-enedioate 3d.
4-Methyl hydrogen (Z )-2-(1-methoxy-1-methylpropyl)but-2-
enedioate 5b. Colourless oil (Found: C, 55.5; H, 7.3. C H O
requires C, 55.6; H, 7.4%); νmax(film)/cm 3600–2800m br,
1
0
16
5
Ϫ1
Colourless oil (Found: C, 58.9; H, 8.1. C H O requires C,
2926s, 1732s, 1646m, 1462m, 1438m, 1379m, 1329m, 1260m,
1
2
20
5
Ϫ1
5
2
1
9.0; H, 8.2%); νmax(film)/cm
877m, 1728s, 1651m, 1461m, 1437m, 1347m, 1265s, 1201s,
169s, 1086w, 1052w, 1019m and 974w; δ 0.88 (3 H, t, J 7.35,
3510m br, 2961s, 2935m,
1176s, 1079m and 899w; δ 0.88 (3 H, t, J 7.43, Me), 1.39 (3 H,
H
s, Me), 1.77 (2 H, q, J 7.43, CH ), 3.22 (3 H, s, OMe), 3.77 (3 H,
2
+
s, CO Me) and 6.00 (1 H, s, ᎐CH); m/z 216 (M , absent), 184
H
2
Me), 0.91 (3 H, t, J 7.27, Me), 1.17–1.66 (5 H, m, CH CHCH ),
(<0.5%), 169 (4), 156 (7), 155 (66), 141 (9), 140 (6), 125 (6), 112
(6), 97 (13), 83 (100), 81 (6), 79 (5), 69 (3), 67 (3), 65 (3), 59 (3)
and 53 (17).
2
2
3
.74 (3 H, s, CO Me), 3.83 (3 H, s, CO Me), 4.49 (1 H, dd, J 3.84
2
2
+
and 1.67, CHOH) and 6.13 (1 H, d, J 1.67, ᎐CH); m/z 244 (M ,
᎐
absent), 213 (1%), 174 (4), 173 (4), 143 (9), 142 (100), 141 (21),
4-Methyl hydrogen (Z )-2-(1-methoxycyclohexyl)but-2-ene-
dioate 5c. Colourless oil (Found: C, 59.6; H, 7.3. C H O
requires C, 59.5; H, 7.4%); νmax(film)/cm 3600–2800m br,
1
40 (14), 113 (7), 110 (50), 99 (6), 82 (7), 71 (8), 69 (4), 59 (9), 55
1
2
18
5
Ϫ1
(10) and 53 (8).
Dibutyl (Z )-2-(1-hydroxy-1-methylethyl)but-2-enedioate 3e.
2940s, 1732s, 1645m, 1437m, 1324m, 1198s and 1072m; δ 1.15–
H
1
52
J. Chem. Soc., Perkin Trans. 1, 1997

View Article Online
2
.07 (10 H, m, 5 CH ), 3.19 (3 H, s, OMe), 3.76 (3 H, s, CO Me)
(6), 125 (23), 124 (11), 114 (100), 113 (49), 99 (6), 97 (7), 85 (12),
82 (17), 69 (9), 59 (25) and 53 (66).
2
2
+
and 6.00 (1 H, s, ᎐CH); m/z 242 (M , absent), 210 (4%), 195 (3),
᎐
1
(
1
(
80 (36), 167 (100), 166 (91), 154 (28), 153 (54), 152 (40), 151
45), 139 (54), 137 (39), 135 (13), 123 (29), 121 (15), 110 (28),
09 (58), 105 (31), 95 (82), 91 (26), 82 (30), 81 (27), 79 (35), 77
33), 69 (24), 67 (20), 65 (24), 59 (4), 55 (31) and 53 (51).
,5-Dimethoxy-3-(1-hydroxy-1-methylethyl)-1-oxacyclopent-
-en-2-one 6a. Colourless oil (Found: C, 53.6; H, 6.8. C H O
3-[(Z )-Methoxycarbonyl)methylene]-1-oxacyclopentan-2-one
13g. Colourless oil (Found: C, 53.7; H, 5.2. C H O requires C,
7
8
4
Ϫ1
53.8; H, 5.1%); νmax(film)/cm 2995m, 2955m, 2927w, 1763s,
1735s, 1677m, 1435m, 1377m, 1335m, 1259s, 1183s, 1102m,
1009s, 959w and 898m; δH 3.06 (2 H, td, J 7.17 and 2.64,
CH C᎐), 3.83 (3 H, s, CO Me), 4.42 (2 H, t, J 7.17, CH OC᎐O)
5
3
9
14
5
2
2
2
Ϫ1
+
requires C, 53.5; H, 6.9%); νmax(film)/cm 3450m br, 2954s,
and 6.38 (1 H, t, J 2.64, ᎐CH); m/z 156 (M , 2%), 127
᎐
2
1
927s, 2850m, 1773s, 1633w, 1463m, 1365m, 1303s, 1195s,
181s, 1139s, 1080m, 1001s, 937s, 880w, 835w, 791w and 737w;
(33), 125 (100), 124 (99), 112 (44), 99 (24), 97 (62), 96 (54), 82
(35), 81 (19), 69 (84), 68 (20), 59 (94), 55 (12) and 53 (55).
3-[(Z )-(Methoxycarbonyl)methylene]-5-methyl-1-oxacyclo-
pentan-2-one 13h. Colourless oil (Found: C, 56.4; H, 6.0.
δH 1.53 (6 H, s, 2 Me), 3.44 (6 H, s, 2 OMe) and 6.72 (1 H, s,
+
᎐
᎐
CH); m/z 202 (M , absent), 187 (17%), 171 (21), 159 (3), 155
Ϫ1
(
(
17), 153 (28), 143 (11), 139 (11), 127 (12), 113 (36), 111 (16), 99
100), 85 (15), 83 (15), 69 (20), 59 (53) and 53 (18).
C H O requires C, 56.5; H, 5.9%); νmax(film)/cm 2981m,
8
10
4
2954m, 1761s, 1735s, 1677m, 1435m, 1387w, 1343m, 1261s,
5
,5-Dibutoxy-3-(1-hydroxy-1-methylethyl)-1-oxacyclopent-3-
en-2-one 6e. Colourless oil (Found: C, 62.7; H, 9.0. C H O
5
1185s, 1108w, 1083m, 1040w, 1011m and 947w; δ 1.45 (3 H, d,
J 6.29, Me), 2.62 (1 H, distorted ddd, J 17.26, 6.31 and 2.84,
CHH), 3.15 (1 H, distorted ddd, J 17.26, 7.25 and 2.34, CHH),
H
1
5
26
Ϫ1
requires C, 62.9; H, 9.1%); νmax(film)/cm 3521m br, 2961s,
935m, 2875w, 1771s, 1462m, 1287s, 1173s and 733m; δH 0.92
6 H, t, J 7.36, 2 Me), 1.30–1.50 (4 H, m, 2 CH ), 1.50–1.77 (4
2
3.83 (3 H, s, CO Me), 4.64–4.77 (1 H, m, CHOC᎐O) and 6.31–
2
+
(
6.35 (1 H, m, ᎐CH); m/z 170 (M , <0.5%), 155 (5), 139 (34), 138
2
᎐
H, m, 2 CH ), 1.53 (6 H, s, 2 Me), 3.54–3.75 (4 H, m, 2
(28), 127 (47), 123 (12), 110 (100), 99 (33), 95 (15), 83 (13), 69
(21), 67 (23), 59 (37) and 53 (10).
2
+
CH OC᎐O) and 6.72 (1 H, s, ᎐CH); m/z 286 (M , absent), 271
2
(3%), 229 (1), 213 (32), 183 (5), 157 (46), 141 (28), 139 (100), 127
(22), 124 (7), 113 (25), 111 (36), 99 (8), 95 (8), 83 (16), 59 (17), 57
(39) and 55 (12).
4,4-Dimethyl-3-[(Z )-methoxycarbonyl)methylene]-1-oxa-
cyclopentan-2-one 13i. Colourless oil (Found: C, 58.6; H, 6.4.
Ϫ1
C H O requires C, 58.7; H, 6.5%); νmax(film)/cm 2967m,
9
12
4
5
,5-Dimethoxy-3-(1-hydroxyethyl)-1-oxacyclopent-3-en-2-one
1760s, 1735s, 1669m, 1614w, 1463m, 1435m, 1367m, 1327m,
6
f. This compound was obtained as a 3:7 mixture with 3f. Sig-
1267m, 1224m, 1141m, 1053m, 1012m, 902w and 790w; δ 1.31
H
Ϫ1
nals reported here refer to 6f only; νmax(film)/cm 1776s; δ 1.46
(6 H, s, 2 Me), 3.84 (3 H, s, CO Me), 4.08 (2 H, s, CH ) and 6.21
H
2
2
+
(3 H, d, J 6.60, Me), 3.44 (6 H, s, 2 OMe), 4.67 (1 H, qd, J 6.60
(1 H, s, ᎐CH); m/z 184 (M , 6%), 169 (3), 154 (50), 153 (82), 152
᎐
+
and 1.60, CHOH) and 6.86 (1 H, d, J 1.60, ᎐CH); m/z 188 (M ,
absent), 173 (5%), 157 (41), 141 (8), 129 (16), 115 (10), 113 (11),
(14), 140 (40), 139 (20), 127 (24), 126 (92), 125 (100), 124 (18),
111 (57), 97 (39), 96 (21), 95 (21), 94 (16), 83 (16), 81 (43), 79
(28), 67 (78), 66 (24), 65 (25), 59 (41), 55 (17) and 53 (66).
4-[(Z )-Methoxycarbonyl)methylene]-cis-2-oxabicyclo[3.3.0]-
octan-3-one 13j. White solid, mp 45–46 ЊC (Found: C, 61.2; H,
᎐
1
5
10 (6), 99 (100), 97 (30), 91 (4), 85 (10), 82 (7), 71 (10), 69 (21),
9 (29), 55 (25) and 53 (28).
Dibutyl (Z )-2-(1-butoxy-1-methylethyl)but-2-enedioate 7e.
Ϫ1
Colourless oil (Found: C, 66.8; H, 10.0. C H O requires C,
6.1. C H O requires C, 61.2; H, 6.1%); νmax(KBr)/cm
1
9
34
5
10 12
4
Ϫ1
6
1
6.7; H, 9.9%); νmax(film)/cm 2959s, 2934m, 2873m, 1731s,
645w, 1465m, 1383m, 1338m, 1249m, 1171s, 1071m, 1037w
2977m, 2961m, 1753s, 1723s, 1669m, 1431m, 1369m, 1329m,
1264m, 1199m, 1185m, 1148m 1096m, 1034m, 1013m, 913w,
and 735m; δ 0.91 (3 H, t, J 7.20, Me), 0.93 (3 H, t, J 7.23, Me),
772w and 650w; δ 1.52–1.85 (4 H, m, ring), 1.92–2.15 (2 H, m,
H
H
0
.95 (3 H, t, J 7.21, Me), 1.30–1.75 (12 H, m, 3 CH CH ), 1.41
ring), 3.41–3.51 (1 H, m, 5-H), 3.84 (3 H, s, CO Me), 4.98–5.06 (1
2
2
2
+
(6 H, s, 2 Me), 3.34 (2 H, t, J 6.78, CH O), 4.12 (2 H, t J 6.70,
H, m, 1-H) and 6.33 (1 H, d, J 2.25, ᎐CH); m/z 196 (M , 15%),
2
᎐
CH OC᎐O), 4.24 (2 H, t, J 6.78, CH OC᎐O) and 5.97 (1 H, s,
165 (81), 164 (27), 152 (37), 140 (100), 139 (42), 137 (65), 136
(74), 124 (18), 119 (17), 112 (15), 111 (25), 109 (44), 108 (70),
107 (33), 95 (31), 93 (25), 91 (47), 81 (53), 80 (49), 79 (80), 77
(36), 74 (14), 67 (36), 59 (50) and 53 (41).
2
2
+
᎐
CH); m/z 342 (M , absent), 327 (3%), 271 (2), 253 (2), 241 (2),
18 (8), 197 (12), 196 (22), 195 (10), 185 (3), 156 (6), 141 (70),
40 (100), 139 (49), 129 (3), 115 (15), 113 (8), 112 (22), 111 (25),
3 (14), 67 (7), 59 (49), 57 (39) and 55 (10).
᎐
2
1
8
4-[(Z )-(Methoxycarbonyl)methylene]-trans-2-oxabicyclo-
[3.3.0]octan-3-one 13k. White solid, mp 83–84 ЊC (Found: C,
61.2; H, 6.2. C H O requires C, 61.2; H, 6.1%); νmax(KBr)/
4
-Methyl hydrogen (Z )-2-(1-hydroxycyclohexyl)but-2-ene-
dioate 8c. Colourless oil (Found: C, 58.0; H, 7.1. C H O
1
1
16
5
10 12
4
Ϫ1
Ϫ1
requires C, 57.9; H, 7.0%); νmax(film)/cm 3600–2800m, br,
940s, 1732s, 1607m, 1437m, 1260s and 1172s; δH 1.15–2.07
10 H, m, 5 CH ), 3.76 (3 H, s, CO Me) and 5.77 (1 H, s, ᎐CH);
cm 2991w, 2959w, 1767s, 1730s, 1679m, 1435m, 1306m, 1259s,
1175m, 1136m, 1115m, 1055w, 1006m, 939w, 910w and 882w;
δH 1.43–1.80 (2 H, m, ring), 1.87–2.27 (4 H, m, ring), 2.69 (1 H,
2
(
2
2
+
m/z 228 (M , absent), 178 (77%), 150 (64), 149 (24), 135 (11), 132
tdd, J 11.61, 6.25 and 3.14, 5-H), 3.78–3.90 (1 H, m, 1-H), 3.82
+
(
(
47), 131 (21), 122 (33), 105 (100), 104 (37), 103 (24), 94 (19), 91
67), 79 (45), 78 (57), 77 (40), 65 (21), 63 (23) and 53 (14).
Dimethyl (E)-2-(1-methoxyethyl)but-2-enedioate 10f. Colour-
(3 H, s, CO Me) and 6.10 (1 H, d, J 3.14, ᎐CH); m/z 196 (M ,
2
6%), 165 (19), 164 (17), 150 (15), 140 (32), 137 (17), 136 (100),
112 (40), 109 (16), 108 (21), 91 (19), 81 (29), 79 (23), 77 (14), 65
(10), 59 (18) and 53 (28).
less oil (Found: C, 53.4; H, 6.9. C H O requires C, 53.5; H,
9
14
5
Ϫ1
6
1
.9%); νmax(film)/cm 2986w, 2954m, 1725s, 1651w, 1436m,
364w, 1258s, 1216s, 1119m, 1010m, 898w and 867w; δH 1.49
Dimethyl (Z )-2-(2-hydroxyethyl)but-2-enedioate 14g. Colour-
less oil (Found: C, 51.0; H, 6.5. C H O requires C, 51.1; H,
8
12
5
Ϫ1
(
3 H, d, J 6.60, Me), 3.27 (3 H, s, OMe), 3.78 (3 H, s, CO Me),
6.4%); νmax(film)/cm 3435m br, 2955m, 2888w, 1737s, 1650m,
2
3
.82 (3 H, s, CO Me), 4.81 (1 H, qd, J 6.60 and 0.60, CHOMe)
1437m, 1371m, 1275s, 1205s, 1172s, 1123w, 1045m, 974w and
2
+
and 6.63 (1 H, d, J 0.60, ᎐CH); m/z 202 (M , absent), 187 (12%),
756w; δH 2.59 (2 H, td, J 6.12 and 1.23, CH ), 3.73 (3 H, s,
᎐
2
1
71 (29), 170 (100), 159 (7), 155 (13), 142 (19), 139 (25), 127
CO Me), 3.79 (2 H, t, J 6.12, CH OH), 3.84 (3 H, s, CO Me)
2
2
2
+
(15), 123 (5), 113 (21), 112 (36), 111 (19), 97 (11), 83 (74), 75
43), 69 (12), 59 (69) and 53 (32).
and 5.97 (1 H, t, J 1.23, ᎐CH); m/z 188 (M , absent), 157 (14%),
126 (100), 125 (32), 99 (14), 98 (43), 69 (34), 68 (39), 67 (19), 59
(40) and 53 (15).
(
4
-(Methoxycarbonyl)-5-methyl-1-oxacyclopent-3-en-2-one
1
5
1
7
1f. Colourless oil (Found: C, 53.7; H, 5.2. C H O requires C,
Dimethyl (Z )-2-(2-hydroxypropyl)but-2-enedioate 14h. Col-
ourless oil (Found: C, 53.4; H, 6.8. C H O requires C, 53.5; H,
7
8
4
Ϫ1
3.8; H, 5.1%); νmax(film)/cm 2992w, 2958m, 1774s, 1730s,
635w, 1439m, 1358m, 1300m, 1233s, 1163m, 1060m, 960m and
66m; δH 1.59 (3 H, dd, J 6.75 and 0.24, Me), 3.91 (3 H, s,
9
14
5
Ϫ1
6.9%); νmax(film)/cm
3443m br, 2995m, 1725s, 1649m,
1437m, 1373m, 1273s, 1202s, 1172s, 1129m, 1082w, 1015w,
CO Me), 5.29 (1 H, qd, J 6.75 and 1.94, CHOC᎐O) and 6.67 (1
972w, 943w and 843w; δ 1.25 (3 H, d, J 6.21, Me), 2.43 (1 H,
distorted ddd, J 14.07, 8.41 and 1.05, CHH), 2.53 (1 H, dis-
2
H
+
H, dq, J 1.94 and 0.24, ᎐CH); m/z 156 (M , 3%), 141 (23), 127
᎐
J. Chem. Soc., Perkin Trans. 1, 1997
153

View Article Online
torted ddd, J 14.07, 4.12 and 1.39, CHH), 3.74 (3 H, s, CO Me),
References
2
3
.85 (3 H, s, CO Me), 3.93–4.11 (1 H, m, CHOH) and 5.92–5.96
2
+
1 (a) T. A. Geissman and M. A. Irwin, Pure Appl. Chem., 1970, 21,
67; (b) S. M. Kupchan, Pure Appl. Chem., 1970, 21, 227; (c) K.-H.
Lee, C. Piantadosi, E.-S. Huang, J. S. Panago and T. A. Geissman,
Cancer Res., 1971, 31, 1649; (d) A. Pommier and J. M. Pons,
Synthesis, 1993, 441.
(a) T. F. Murray, E. G. Samsel, V. Varma and J. R. Norton, J. Am.
Chem. Soc., 1981, 103, 7520; (b) J. R. Norton, K. E. Shenton and
J. Schwartz, Tetrahedron Lett., 1975, 51; (c) E. Drent, P. H. M.
Budzelaar and W. W. Jager, EP Appl. 386 833/1990 (Chem. Abstr.,
1991, 114, 142679z); (d) E. Drent, P. Arnoldy and P. H. M.
Budzelaar, J. Organomet. Chem., 1993, 455, 247.
(
(
(
1 H, m, ᎐CH); m/z 202 (M , absent), 187 (<0.5%), 171 (3), 158
5), 139 (12), 127 (20), 126 (100), 99 (11), 98 (39), 69 (20), 68
30), 67 (15), 59 (26) and 53 (6).
᎐
1
Dimethyl (Z )-2-[trans-(2-hydroxycyclopentyl)]but-2-enedioate
2
1
4k. Colourless oil (Found: C, 58.1; H, 7.0. C H O requires
11 16 5
Ϫ1
C, 57.9; H, 7.0%); νmax(film)/cm 3439m, br, 2954s, 2877w,
1
9
718s, 1644m, 1437m, 1378m, 1271s, 1201s, 1171s, 1019m,
75w, 873w and 756m; δH 1.53–1.87 (4 H, m, ring), 1.90–2.10
(
2 H, m, ring), 2.56-2.73 (1 H, m, CHC᎐), 3.72 (3 H, s, CO Me),
᎐
2
3
.84 (3 H, s, CO Me), 4.10–4.21 (1 H, m, CHOH) and 5.90
3 Y. Tamaru, M. Hojo and Z.-I. Yoshida, J. Org. Chem., 1991, 56,
099.
2
+
1
(1 H, d, J 1.22, ᎐CH); m/z 228 (M , absent), 197 (12%), 196 (24),
᎐
4
(a) T. Nogi and J. Tsuji, Tetrahedron, 1969, 25, 4099; (b) J. Tsuji and
T. Nogi, Tetrahedron Lett., 1966, 1801; (c) B. El Ali and H. Alper,
J. Org. Chem., 1991, 56, 5357; (d) K.-T. Huh, A. Orita and H. Alper,
J. Org. Chem., 1993, 58, 6956; (e) K. Matsushita, T. Komori, S. Oi
and Y. Inoue, Tetrahedron Lett., 1994, 35, 5889.
1
68 (22), 164 (16), 152 (48), 140 (100), 139 (41), 137 (79), 136
(50), 124 (23), 112 (18), 111 (28), 109 (61), 108 (36), 107 (16), 96
(16), 93 (13), 91 (18), 81 (53), 80 (28), 79 (49), 67 (20), 59 (74), 55
(22) and 53 (28).
Methyl 4,4-dimethyl-5-hydroxypent-2-ynoate 15i. Colourless
5 I. Matsuda, A. Ogiso and S. Sato, J. Am. Chem. Soc., 1990, 112,
120.
6 B. Gabriele, M. Costa, G. Salerno and G. P. Chiusoli, J. Chem. Soc.,
Chem. Commun., 1994, 1429.
6
oil (Found: C, 61.3; H, 7.8. C H O requires C, 61.5; H, 7.7%);
8
12
3
Ϫ1
νmax(film)/cm
3443m br, 2972m, 2874w, 2235m, 1717s,
1
2
(
9
5
436m, 1295m, 1261s, 1061m, 1028m and 754w; δ 1.27 (6 H, s,
H
7
B. Gabriele, M. Costa, G. Salerno and G. P. Chiusoli, J. Chem. Soc.,
Perkin Trans. 1, 1994, 83.
Me), 3.50 (2 H, s, CH ) and 3.77 (3 H, s, CO Me); m/z 156
2
2
+
M , absent), 155 (<0.5%), 126 (100), 125 (63), 111 (44), 95 (21),
8 (a) T. F. Murray and J. R. Norton, J. Am. Chem. Soc., 1979, 101,
4107; (b) T. F. Murray, V. Varma and J. R. Norton, J. Am. Chem.
Soc., 1977, 99, 8087.
4 (97), 93 (18), 83 (25), 82 (20), 79 (42), 67 (74), 66 (25), 65 (23),
9 (16) and 53 (26).
9
F. Calderazzo, Angew. Chem., Int. Ed. Engl., 1977, 16, 299.
4
-[(E)(Methoxycarbonyl)methylene]-trans-2-oxabicyclo-
1
0 (a) B. Gabriele, G. Salerno, M. Costa and G. P. Chiusoli,
J. Organomet. Chem., 1995, 503, 21 and references cited therein;
(b) R. F. Heck, J. Am. Chem. Soc., 1972, 94, 2712.
[
3.3.0]octan-3-one 16k. Colourless oil (Found: C, 61.0; H, 6.2.
Ϫ1
C H O requires C, 61.2; H, 6.1%); νmax(film)/cm 2957w,
1
0
12
4
2
1
(
922m,1781s,1730s,1437m,1343w,1265s,1209m,1175m,1125m,
11 P. G. Sammes and D. J. Weller, Synthesis, 1995, 1205 and references
052m, 1015m and 739s; δ 1.55–1.85 (2 H, m, ring), 1.90–2.06
cited therein.
H
1
1
2 F. Barbot and P. Miginiac, J. Organomet. Chem., 1992, 440, 249.
3 M. M. Midland, J. Org. Chem., 1975, 40, 2250.
1 H, m, ring), 2.10–2.24 (2 H, m, ring), 2.25–2.45 (1 H, m, ring),
2
.72–2.85 (1 H, m, 5-H), 3.76–3.93 (1 H, m, 1-H), 3.79 (3 H, s,
+
14 J. Tsuji, T. Sugiura and I. Minami, Tetrahedron Lett., 1986, 27, 731.
CO Me) and 6.68 (1 H, d, J 3.52, ᎐CH); m/z 196 (M , <0.5%),
2
1
(
1
(
65 (32), 164 (12), 152 (53), 140 (54), 139 (28), 137 (48), 136
100), 124 (27), 120 (17), 113 (23), 112 (20), 111 (37), 109 (58),
08 (46), 107 (24), 97 (11), 96 (21), 91 (30), 81 (62), 80 (35), 79
65), 77 (33), 67 (22), 65 (33), 59 (72), 55 (28) and 53 (46).
Paper 6/03892A
Received 4th June 1996
Accepted 9th September 1996
1
54
J. Chem. Soc., Perkin Trans. 1, 1997