Synthesis of 2-ynamides by direct palladium-catalyzed oxidative aminocarbonylation of alk-1-ynes

Article abstract of DOI:10.1016/S0022-328X(00)00795-6

A novel synthesis of 2-ynamides (3) by palladium-catalyzed oxidative aminocarbonylation of alk-1-ynes (1) is reported. Reactions are catalyzed by PdI₂/KI and are carried out at 100°C in dioxane as the solvent in the presence of dialkylamines (2) as nucleophiles (amine/alk-1-yne molar ratio=1/1) using a 4/1 CO/air mixture (20 atm total pressure at 25°C).

Full text of DOI:10.1016/S0022-328X(00)00795-6

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 622 (2001) 84–88
Synthesis of 2-ynamides by direct palladium-catalyzed oxidative
aminocarbonylation of alk-1-ynes
Bartolo Gabriele* a,1, Giuseppe Salerno* a,2, Lucia Veltri a, Mirco Costa b
a Dipartimento di Chimica, Uni6ersita` della Calabria, 87030 Arca6acata di Rende, Cosenza, Italy
b Dipartimento di Chimica Organica e Industriale, Uni6ersita` di Parma, Parco Area delle Scienze, 43100 Parma, Italy
Received 20 September 2000; accepted 20 October 2000
Abstract
A novel synthesis of 2-ynamides (3) by palladium-catalyzed oxidative aminocarbonylation of alk-1-ynes (1) is reported.
Reactions are catalyzed by PdI2/KI and are carried out at 100°C in dioxane as the solvent in the presence of dialkylamines (2)
as nucleophiles (amine/alk-1-yne molar ratio=1/1) using a 4/1 CO/air mixture (20 atm total pressure at 25°C). © 2001 Elsevier
Science B.V. All rights reserved.
Keywords: Alk-1-ynes; Amides; Aminocarbonylation; Carbonylation; Palladium; 2-Ynamides
1. Introduction
alcohols proved to be ineffective, as shown by the
following experiments. The reaction between pheny-
lacetylene and diethylamine carried out using the sys-
tem PdCl2/CuCl2/AcONa under the conditions
described in Ref. [4a] using diethylamine as the solvent
in place of methanol gave only a 5% yield of the
diethylamide of 3-phenylpropynoic acid 3c, the main
reaction product being 1,4-diphenyl-1,3-butadiyne
(34%) at total substrate conversion. Practically the
same results were obtained with dioxane as the solvent
using a 1/1 molar ratio phenylacetylene/diethylamine
(6% of 3c, 41% of 1,4-diphenyl-1,3-butadiyne at total
substrate conversion).
2-Ynamides (3) are useful intermediates for the syn-
thesis of some biologically active molecules [1] and
heterocyclic derivatives [2]. They are generally prepared
by Pd/Cu-catalyzed reaction between alk-1-ynes and
carbamoyl chlorides [1,3]. The possibility to obtain 3 by
direct aminocarbonylation of alk-1-ynes 1 appears
therefore synthetically attractive. However, although
the catalytic oxidative monocarbonylation of 1 with
alcohols as nucleophiles to obtain alkynyl esters has
been known for many years [4], to our knowledge no
analogous catalytic aminocarbonylation [5] has been
described to date. The only example reported in the
literature of formation of 3 from 1, 2 and CO involves
a non-catalytic reaction promoted by a Ni(II) complex
[6].
We now wish to report the Pd-catalyzed aminocar-
bonylation of 1, which occurs under relatively mild
conditions and affords 3 in satisfactory yields (Eq. 1).
The application of the Pd-catalyzed oxidative mono-
carbonylation methodology [4] to the synthesis of 2-
ynamides using amines as nucleophiles rather than
1 *Corresponding author. Fax: +39-0984-492044; e-mail:
b.gabriele@unical.it
(1)
2 *Corresponding author. E-mail: g.salerno@unical.it
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(00)00795-6

B. Gabriele et al. / Journal of Organometallic Chemistry 622 (2001) 84–88
85
side-reaction resulting from amine addition to the triple
bond with formation of a 21% yield of (E)-diethyl-[2-
(4-nitrophenyl)vinyl]amine 5g took place, which low-
ered the yield of the desired product 3g to 32% (entry
7).
2. Results and discussion
This new method consists of the reaction of alk-1-
ynes (1) and dialkylamines (2) (1/1 molar ratio) at
100°C with carbon monoxide and oxygen (CO/air=4/
1, 20 atm total at 25°C) in dioxane as the solvent in the
presence of PdI2 (0.2 mol%) and KI (2 mol%) [7].
Representative results are collected in Table 1.
Both alky- and arylacetylenes could be used success-
fully, the latter being consistently more reactive (com-
pare entries 1–2 with entries 3–9). Moreover,
alkylacetylenes also gave small amounts of products
resulting from oxidative diaminocarbonylation of the
triple bond, i.e. bis-diethylamides of alkylmaleic acid 4
(4–9%, entries 1–2). Thus, the reaction between hex-1-
yne or t-butylacetylene with CO, oxygen and diethy-
lamine afforded after 24 h, 3a (58%) or 3b (42%)
together with 4a (9%) or 4b (4%) at 71% or 50%
substrate conversion, respectively (entries 1, 2). Practi-
cally the same results were obtained when the reaction
time was prolonged to 48 h or when a molar ratio
1/PdI2 of 200 (with KI/PdI2=10) was used instead of
500.
A nucleophilic secondary amine such as diethylamine
(entries 1–7), dibutylamine (entry 8) or morpholine
(entry 9) was required for the reaction to occur, hin-
dered amines (such as diisopropylamine) or amines of
low basicity (like N-methylaniline) being unreactive. On
the other hand, the use of primary amines led to
complex reaction mixtures, in which the 2–alkynamides
were present in only limited amounts. The main reac-
tion products in this case resulted from oxidative car-
bonylation of the amino group, with formation of
ureas, as indicated by GLC-MS analysis.
According to what previously proposed for the for-
mation of alkynyl esters by PdCl2-catalyzed oxidative
monoalkoxycarbonylation of alk-1-ynes [4], the cata-
lytic process leading to 3 should occur via formation of
an alkynylpalladium species as the key intermediate.
This species, which is apparently stabilized by iodide
ligands, results from the reaction between the alk-1-yne,
PdI2 and the amine (Scheme 1; anionic iodide ligands
are omitted for simplicity). Subsequent carbon monox-
ide insertion into the carbon-palladium bond followed
by nucleophilic displacement by the amine affords
product 3 and Pd(0), whose reoxidation according to
the usual mechanism [7] regenerates the catalytically
active species PdI2. Attack by the amine on the
Arylacetylenes could bear p-donor as well as p-accep-
tor substituents (entries 4–7). Indeed, reaction kinetics
and product yields were quite insensitive to the nature
of the substituent on the ring (compare entries 3–6),
with the exception of p-nitrophenylacetylene, whose
conversion rate was higher with respect to the other
arylacetylenes tested. With this substrate, however, a
Table 1
Synthesis of 2-alkynylamides 3 by PdI2/KI-catalyzed oxidative aminocarbonylation of alk-1-ynes 1 a
Run
R
2
Conversion of 1 (%) b
Yield of 3 (%) c
1
2
3
4
Bu
t-Bu
Ph
p-MeOC6H4
p-BrC6H4
p-NCC6H4
p-O2NC6H4
Ph
Et2NH
Et2NH
Et2NH
Et2NH
Et2NH
Et2NH
Et2NH
Bu2NH
Morpholine
71
50
90
83
82
95
100
90
3a
3b
3c
3d
3e
3f
3g
3h
3i
58 (54) d
42 (36) e
81 (73)
80 (73)
74 (68)
70 (66)
32 (28) g
70 (62)
70 (64)
5
6
7 f
8
9
Ph
93
a Unless otherwise noted, all reactions were carried out in dioxane (0.5 mmol of 1/ml of dioxane, 10 mmol scale based on 1) using a 1/1 molar
ratio 1/2 at 100°C for 24 h under 20 atm of a 4/1 mixture of CO/air in the presence of PdI2 (0.2%) and KI (2%).
b Determined by GLC.
c GLC yield (isolated yield) based on starting 1.
d Bis-diethylamide of butylmaleic acid 4a (9% GLC yield, 6% isolated) was also present in the reaction mixture.
e Bis-diethylamide of t-butylmaleic acid 4b (4% GLC yield, 2% isolated) was also present in the reaction mixture.
f The reaction time was 15 h.
g (E)-Diethyl-[2-(4-nitrophenyl)vinyl]amine 5g was also formed in 21% GLC yield.

86
B. Gabriele et al. / Journal of Organometallic Chemistry 622 (2001) 84–88
Moreover, catalytic efficiencies as high as 400 mol of 3
per mol of catalyst used have been achieved.
3. Experimental
3.1. General
Melting points were determined on a Reichert Ther-
movar melting point apparatus and are uncorrected.
Elemental analyses were carried out with a Carlo Erba
Elemental Analyzer Mod. 1106. 1H-NMR and 13C-
NMR spectra were taken on a Bruker AC300 spec-
trometer and run on CDCl3 solutions with Me4Si as
internal standard and recorded at 300 and 75 MHz,
respectively. Chemical shifts and coupling constants (J)
are given in ppm (l) and in Hz, respectively. IR spectra
were taken on a Perkin-Elmer Paragon 1000 PC FT-IR
spectrometer. Mass spectra were obtained using an HP
5972A GC-MS apparatus at 70 eV ionization voltage.
All reactions were analyzed by TLC on silica gel 60 F254
or by GLC using a Shimadzu GC-14A gas chro-
matograph and capillary columns with polymethylsili-
cone+5% phenylsilicone as the stationary phase
(HP-5). Column chromatography was performed on
silica gel 60 (Merck, 70-230 mesh). Dioxane was dis-
tilled over sodium before use. Starting hex-1-yne, t–
Scheme 1.
Scheme 2.
alkynoylpalladium complex apparently requires a suffi-
ciently nucleophilic amine, since as mentioned before,
no aminocarbonylation was observed with hindered
amines. It is worth noting that the possibility to obtain
a 2-ynamide by a sequence of steps strictly analogous to
that proposed starting from a Ni(II) complex has been
demonstrated [6]. The following sequence of reactions
has been carried out: (a) reaction between acetylene,
Ni(PPh3)2Br2 and triethylamine to give an ethynylnickel
complex; (b) reaction of this complex with CO to
obtain the corresponding propynoylnickel complex; (c)
reaction of the latter with diethylamine to form the
diethylamide of propynoic acid and Ni(0).
Side-products 4a–b, i.e. maleic bis-amides, corre-
spond to oxidative dicarbonylation of the triple bond,
and are formed through a competitive reaction path-
way, involving syn addition of a carbamoylpalladium
species to the triple bond followed by carbon monoxide
insertion and nucleophilic displacement by the amine
(Scheme 2). It is important to note that, as previously
reported [7a], oxidative carbonylation of alkyl- and
arylacetylenes catalyzed by the PdI2/KI catalytic system
with alcohols as nucleophiles instead of amines resulted
in exclusi6e formation of maleic derivatives through an
analogous reaction pattern. Clearly, the shift towards
the oxidative monocarbonylation observed in the case
of amines is due to the basicity of the latter, which
promotes the first step showed in Scheme 1, i.e. forma-
tion of the alkynylpalladium species.
butylacetylene,
phenylacetylene,
diethylamine,
dibutylamine, and morpholine were commercially avail-
able and were used without further purification. p-
Methoxyphenylacetylene [8], p-bromophenylacetylene
[9], p-cyanophenylacetylene [10] and p-nitropheny-
lacetylene [8] were prepared according to literature
procedures.
3.2. Typical procedure for oxidati6e aminocarbonylation
of alk-1-ynes
In a typical experiment, a 300 ml stainless steel
autoclave with magnetic stirring was charged in the
presence of air with PdI2 (7.0 mg, 0.019 mmol), KI (32
mg, 0.19 mmol) and a solution of 1 (9.6 mmol) and 2
(9.6 mmol) in dioxane (19 ml). The autoclave was
pressurized with stirring at room temperature with CO
(16 atm) and air (up to 20 atm of total pressure), and
then heated at 100°C with stirring for 24 h. The auto-
clave was then cooled and degassed and products sepa-
rated as described below.
3.3. Separation of products
Products 3a–f and 3h–i were easily isolated by
column chromatography on silica gel after removal of
the solvent under reduced pressure: 3a (0.94 g, 54%)
and 4a (0.16 g, 6%) were eluted in this order using
hexane/AcOEt from 6:4 to 2:8; 3b (0.63 g, 36%) and 4b
In conclusion, we have developed the first example of
catalytic synthesis of 2-ynamides 3 via oxidative
monoaminocarbonylation of alk-1-ynes 1. The reaction
is quite selective and the synthetic procedure is simple.

B. Gabriele et al. / Journal of Organometallic Chemistry 622 (2001) 84–88
87
(54 mg, 2%) were eluted in this order using hexane/
AcOEt from 6:4 to 2:8; 3c (6:4 hexane/AcOEt, 1.41 g,
73%); 3d (6:4 hexane/AcOEt, 1.62 g, 73%); 3e (7:3
hexane/AcOEt, 1.82 g, 68%); 3f (hexane/AcOEt from
7:3 to 6:4, 1.44 g, 66%); 3h (7:3 hexane/AcOEt, 1.54 g,
62%); 3i (hexane/AcOEt from 7:3 to 6:4, 1.33 g, 64%).
Products 3g and 5g were consistently obtained in a
mixture by column chromatography of the crude deriv-
ing from carbonylation of p-nitrophenylacetylene and
diethylamine. In order to obtain pure 3g the reaction
crude was extracted with diethyl ether and washed with
a solution of NH4Cl. The aqueous phase was extracted
with diethyl ether and the combined organic layers
dried over Na2SO4. After filtration and removal of the
solvent by distillation under reduced pressure, column
chromatography (hexane/AcOEt=7:3) afforded 3g
(0.66 g, 28%). Pure product 5g was obtained by the
reaction between p-nitrophenylacetylene (170 mg, 1.16
mmol), diethylamine (85 mg, 1.16 mmol) in dioxane
(2.3 ml) in the presence of PdI2 (1.0 mg, 2.78·10−3
mmol) and KI (4.6 mg, 0.028 mmol) under nitrogen at
100°C for 15 h. The solvent was removed by distillation
under reduced pressure, and column chromatography
(hexane/AcOEt=8:2) afforded 5g (60 mg, 24% yield).
on phenyl ring), 3.83 (s, 3 H, OMe), 3.66 (q, J=7.1, 2
H, CH2CH3), 3.47 (q, J=7.2, 2 H, CH2CH3), 1.28 (t,
J=7.1, 3 H, CH2CH3), 1.17 (t, J=7.2, 3 H, CH2CH3);
13C-NMR l 161.02, 154.33, 134.11, 114.31, 112.89,
89.50, 81.39, 55.40, 43.61, 39.34, 14.44, 12.94; MS m/e
231 (10, M+), 230 (9), 216 (16), 160 (12), 159 (100), 144
(15), 132 (34), 116 (17), 88 (15), 72 (12), 62 (10). Anal.
Calc. for C14H17NO2: C, 72.70; H, 7.41; N, 6.06.
Found: C, 72.95; H, 7.36; N, 6.12%.
3.4.3. Diethylamide of 3-(4-bromophenyl)propynoic acid
(3e)
Yellow solid, m.p. 98–100°C. IR (KBr) 2980 (w),
2936 (w), 2209 (m), 1613 (s), 1480 (s), 1432 (s), 1292
(m), 1062 (m), 1008 (m), 838 (m), 733 (m) cm−1
;
1H-NMR l 7.54–7.48 (m, 2 H on phenyl ring), 7.42–
7.37 (m, 2 H on phenyl ring), 3.65 (q, J=7.2, 2 H,
CH2CH3), 3.48 (q, J=7.1, 2 H, CH2CH3), 1.28 (t,
J=7.2, 3 H, CH2CH3), 1.18 (t, J=7.1, 3 H, CH2CH3);
13C-NMR l 153.74, 133.69, 131.92, 124.50, 119.86,
87.81, 83.11, 43.62, 39.43, 14.44, 12.86; MS m/e 281 (7,
M++2), 280 (15, M++1), 279 (8, M+), 278 (16), 266
(8), 264 (8), 209 (97), 207 (100), 128 (30), 101 (7), 100
(20), 99 (9), 75 (7), 74 (21), 72 (7), 56 (12). Anal. Calc.
for C13H14BrNO: C, 55.73; H, 5.04; Br, 28.52; N, 5.00.
Found: C, 55.66; H, 5.09; Br, 28.91; N, 4.97%.
3.4. Characterization of products
Known products 3a [6b,11], 3c [6a], and 4a [6b] were
characterized by comparison with literature data. As
explained above, product 5g could not be isolated from
the crude reaction deriving from carbonylation of p-ni-
trophenylacetylene and diethylamine, and was charac-
terized by GC-MS comparison with the pure product
obtained by PdI2/KI–catalyzed addition of diethy-
lamine to p-nitrophenylacetylene.
3.4.4. Diethylamide of 3-(4-cyanophenyl)propynoic acid
(3f)
Yellow solid, m.p. 94–95°C. IR (KBr) 2977 (w), 2940
(w), 2225 (m), 1618 (s), 1437 (w), 1250 (m), 832 (m),
731 (m) cm−1 1H-NMR l 7.72–7.62 (m, 4 H on
;
phenyl ring), 3.67 (q, J=7.2, 2 H, CH2CH3), 3.50 (q,
J=7.2, 2 H, CH2CH3), 1.30 (t, J=7.2, 3 H, CH2CH3),
1.20 (t, J=7.2, 3 H, CH2CH3); 13C-NMR l 153.14,
132.76, 132.21, 125.61, 117.98, 113.32, 86.55, 85.40,
43.67, 39.50, 14.48, 12.81; MS m/e 226 (18, M+), 225
(37), 211 (12), 155 (15), 154 (100). Anal. Calc. for
C14H14N2O: C, 74.31; H, 6.24; N, 12.38. Found: C,
74.13; H, 6.27; N, 12.26%.
3.4.1. Diethylamide of 4,4-dimethylpent-2-ynoic acid
(3b)
Yellow oil. IR (neat) 2972 (s), 2935 (m), 2228 (m),
1628 (s), 1459 (m), 1426 (s), 1282 (m), 1155 (w), 738 (w)
1
cm−1; H-NMR l 3.55 (q, J=7.1, 2 H, CH2CH3), 3.41
(q, J=7.1, 2 H, CH2CH3), 1.29 (s, 9 H, t-Bu), 1.21 (t,
J=7.1, 3 H, CH2CH3), 1.13 (t, J=7.1, 3 H, CH2CH3);
13C-NMR l 154.33, 98.78, 73.19, 43.61, 39.32, 30.26,
27.74, 14.25, 12.91; MS m/e 181 (13, M+), 180 (8), 166
(29), 138 (16), 125 (19), 124 (8), 110 (13), 109 (100), 81
(41), 79 (25), 67 (9), 65 (8), 53 (15). Anal. Calc. for
C11H19NO: C, 72.88; H, 10.56; N, 7.73. Found: C,
72.55; H, 10.60; N, 7.77%.
3.4.5. Diethylamide of 3-(4-nitrophenyl)propynoic acid
(3g)
Yellow solid, m.p. 113–115°C. IR (KBr) 2984 (w),
2937 (w), 2224 (w), 1615 (s), 1519 (s), 1434 (m), 1345
1
(s), 1100 (m), 859 (m) cm−1; H-NMR l 8.27–8.21 (m,
2 H on phenyl ring), 7.74–7.68 (m, 2 H on phenyl ring),
3.69 (q, J=7.1, 2 H, CH2CH3), 3.51 (q, J=7.1, 2 H,
CH2CH3), 1.31 (t, J=7.1, 3 H, CH2CH3), 1.21 (t,
J=7.1, 3 H, CH2CH3); 13C-NMR l 153.11, 148.18,
133.14, 127.52, 123.74, 86.31, 86.02, 43.74, 39.56, 14.49,
12.81; MS m/e 246 (14, M+), 245 (32), 231 (14), 175
(11), 174 (100), 144 (6), 128 (33), 116 (7), 100 (11), 74
(10). Anal. Calc. for C13H14N2O3: C, 63.40; H, 5.73; N,
11.38. Found: C, 63.62; H, 5.77; N, 11.28%.
3.4.2. Diethylamide of 3-(4-methoxyphenyl)propynoic
acid (3d)
Yellow solid, m.p. 59–60°C. IR (KBr) 2979 (w), 2935
(w), 2200 (m), 1628 (s), 1601 (m), 1508 (m), 1431 (m),
1
1250 (m), 1136 (m), 1028 (m), 839 (m) cm−1; H-NMR
l 7.51–7.46 (m, 2 H on phenyl ring), 6.91–6.85 (m, 2 H

88
B. Gabriele et al. / Journal of Organometallic Chemistry 622 (2001) 84–88
3.4.6. Dibutylamide of 3-phenylpropynoic acid (3h)
Yellow oil. IR (neat) 2959 (s), 2932 (s), 2873 (m), 2214
(m), 1627 (s), 1425 (m), 1298 (m), 1209 (m), 1140 (m),
Acknowledgements
Financial support from the Ministero dell’Universita`
e della Ricerca Scientifica e Tecnologica is gratefully
acknowledged.
1
758 (m), 691 (m) cm−1; H-NMR l 7.55–7.50 (m, 2 H
on phenyl ring), 7.42–7.32 (m, 3 H on phenyl ring),
3.64–3.57 (m, 2 H, NCH2CH2), 3.44–3.37 (m, 2 H,
NCH2CH2), 1.72–1.25 (m, 8 H, 2 CH2CH2CH3), 0.97 (t,
3 H, J=7.3, CH2CH3), 0.94 (t, 3 H, J=7.3, CH2CH3);
13C-NMR l 154.49, 132.33, 129.84, 128.54, 121.02, 89.27,
82.36, 48.99, 44.71, 31.12, 29.70, 20.27, 20.06, 13.83; MS
m/e 257 (2, M+), 215 (7), 214 (15), 130 (11), 129 (100),
75 (6). Anal. Calc. for C17H23NO: C, 79.33; H, 9.01; N,
5.44. Found: C, 79.72; H, 9.09; N, 5.39%.
References
[1] (a) G. Pattenden, M. Tankard, Tetrahedron Lett. 34 (1993)
2677. (b) L.A. Hay, T.M. Koenig, F.O. Gina, J.D. Copp, D.
Mitchell, J. Org. Chem. 63 (1998) 5050.
[2] (a) Z.T. Fomum, A.E. Nkengfack, G.W.P. Mpango, S.R. Lan-
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Rudorf, R. Schwarz, Heterocycles 24 (1986) 3459.
[3] Y. Tohda, K. Sonogashira, N. Hagihara, Synthesis (1977) 777.
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Valde´s-Pere´z, O.N. Temkin, J. Mol. Catal. A 130 (1998) 29.
(f) Y. Sakurai, S. Sakaguchi, Y. Ishii, Tetrahedron Lett. 40
(1999) 1701.
[5] For some recent examples of Pd-catalyzed aminocarbonylation
of unsaturated substrates, see: (a) C.-Y. Oh, K.-S. Kim, W.-H.
Ham, Tetrahedron Lett. 39 (1998) 2133. (b) H. Harayama, A.
Abe, T. Sakado, M. Kimura, K. Fugami, S. Tanaka, Y.
Tamaru, J. Org. Chem. 62 (1997) 2113. (c) Y. Tamaru, M.
Kimura, Synlett. (1997) 749 and references cited therein. (d)
W. Hu¨mmer, E. Dubois, T. Gracza, V. Ja¨ger, Synthesis (1997)
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J. Org. Chem. 61 (1996) 3238.
3.4.7. 1-Morpholino-4-yl-3-phenylpropynone (3i)
Yellow solid, m.p. 53–54°C. IR (KBr) 2974 (w), 2862
(w), 2215 (m), 1626 (s), 1431 (s), 1280 (m), 1212 (m), 1112
(m), 851 (m), 760 (m), 728 (m), 690 (m) cm−1; 1H-NMR
l 7.57–7.52 (m, 2 H on phenyl ring), 7.44–7.33 (m, 3 H
on phenyl ring), 3.87–3.82 (m, 4 H, CH2OCH2), 3.78–
3.73 (m, 4 H, CH2NCH2); 13C-NMR l 153.26, 132.41,
130.18, 128.59, 120.46, 91.15, 80.94, 66.95, 66.54, 47.39,
42.09; MS m/e 215 (21, M+), 186 (9), 185 (6), 156 (6),
130 (12), 129 (100), 116 (8), 102 (7), 101 (10), 86 (22), 75
(21), 74 (8), 56 (28). Anal. Calc. for C13H13NO2: C, 72.54;
H, 6.09; N, 6.51. Found: C, 72.71; H, 6.03; N, 6.60%.
3.4.8. Bis-diethylamide of (Z)-2-t-butylbut-2-enedioic
acid (4b)
Yellow oil. IR (neat) 2969 (s), 2874 (w), 1631 (s), 1461
(s), 1430 (s), 1258 (m), 1142 (m), 1081 (w) cm−1
;
1H-NMR l 6.04 (s, 1 H, ꢀCH), 3.69–3.21 (m, 8 H, 4
CH2CH3), 1.22 (s, 9 H, t-Bu), 1.22–1.06 (m, 12 H, 4
CH2CH3); 13C-NMR l 169.05, 165.96, 155.07, 117.08,
42.94, 42.77, 40.02, 37.53, 30.11, 14.52, 13.20, 12.48; MS
m/e 282 (M+, absent), 225 (12), 211 (26), 210 (100), 182
(15), 126 (35), 100 (9), 72 (86), 67 (7). Anal. Calc. for
C16H30N2O2: C, 68.04; H, 10.71; N, 9.92. Found: C,
68.21; H, 10.64; N, 9.98%.
[6] (a) H. Hoberg, H.J. Riegel, J. Organomet. Chem. 241 (1983)
245. (b) F.J. Fan˜ana´s, H. Hoberg, J. Organomet. Chem. 277
(1984) 135.
[7] Several examples reported by us have demonstrated the pecu-
liar activity of the PdI24− –based catalytic system in promoting
oxidative carbonylation reactions of alkynes: (a) B. Gabriele,
M. Costa, G. Salerno, G.P. Chiusoli, J. Chem. Soc. Perkin
Trans. 1 (1994) 83. (b) A. Bonardi, M. Costa, B. Gabriele, G.
Salerno, G.P. Chiusoli, Tetrahedron Lett. 36 (1995) 7495. (c)
B. Gabriele, G. Salerno, F. De Pascali, M. Costa, G.P. Chiu-
soli, J. Chem. Soc. Perkin Trans. 1 (1997) 147. (d) A. Bacchi,
G.P. Chiusoli, M. Costa, C. Sani, B. Gabriele, G. Salerno, J.
Organomet. Chem. 562 (1998) 35. (e) G.P. Chiusoli, M. Costa,
B. Gabriele, G. Salerno, J. Mol. Catal. A 143 (1999) 297. (f)
A. Fazio, B. Gabriele, G. Salerno, S. Destri, Tetrahedron 55
(1999) 485. (g) B. Gabriele, G. Salerno, F. De Pascali, M.
Costa, G.P. Chiusoli, J. Org. Chem. 64 (1999) 7693. (h) B.
Gabriele, G. Salerno, F. De Pascali, M. Costa, G.P. Chiusoli,
J. Organomet. Chem. 593–594 (2000) 409.
3.4.9. (E)-Diethyl-[2-(4-nitrophenyl)6inyl]amine (5g)
Brown oil. IR (neat) 2974 (w), 2933 (w), 1631 (m), 1574
(s), 1518 (m), 1345 (s), 1293 (s), 1103 (m), 852 (m) cm−1
;
1H-NMR l 8.01–7.94 (m, 2 H on phenyl ring), 7.13–7.06
(m, 2 H on phenyl ring), 7.04 (d, J=13.7, 1 H,
HCꢀCHN), 5.16 (d, J=13.7, 1 H, HCꢀCHN), 3.26 (q,
J=7.1, 4 H, 2 CH2CH3), 1.20 (t, J=7.1, 6 H, 2
CH2CH3); 13C-NMR l 148.57, 141.90, 124.56, 123.75,
121.99, 94.49, 45.95, 13.34; MS m/e 220 (100, M+), 205
(80), 191 (17), 175 (17), 159 (29), 158 (66), 130 (27), 56
(40). Anal. Calc. for C12H16N2O2: C, 65.43; H, 7.32; N,
12.72. Found: C, 65.28; H, 7.39; N, 12.61%.
[8] E. Negishi, M. Kotora, C. Xu, J. Org. Chem. 62 (1997) 8957.
[9] D.L. Pearson, J.M. Tour, J. Org. Chem. 62 (1997) 1376.
[10] K.A. Hirsch, S.R. Wilson, J.S. Moore, J. Am. Chem. Soc. 119
(1997) 10401.
[11] Z. Zhou, D. Larouche, S.M. Bennet, Tetrahedron 51 (1995)
11623.
.