Tethering strategies in alkynylamino carbene complexes

Article abstract of DOI:10.1016/S0022-328X(00)00636-7

During the synthesis of complex cyclic macromolecular structures, the reaction of different mono- di- and triamino alkynyl metal carbene systems with primary and secondary amines was studied. The results showed the low stability of the metal carbene compl

Full text of DOI:10.1016/S0022-328X(00)00636-7

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Journal of Organometallic Chemistry 617–618 (2001) 334–338
Tethering strategies in alkynylamino carbene complexes
Josep M. Moreto´, Susagna Ricart *
Departament de Qu´ımica Orga`nica i Biolo`gica, IIQAB (CSIC), C/J Girona 18-26, S-08034, Barcelona, Spain
Received 17 July 2000; accepted 7 September 2000
Dedicated to Professor Jose Barluenga on the occasion of his 60th birthday
Abstract
During the synthesis of complex cyclic macromolecular structures, the reaction of different mono- di- and triamino alkynyl
metal carbene systems with primary and secondary amines was studied. The results showed the low stability of the metal carbene
complexes obtained from the conjugate addition of primary amines in contrast to the fairly good stability of the corresponding
complexes obtained from the addition of secondary amines. © 2001 Elsevier Science B.V. All rights reserved.
Keywords: Aminocarbene complexes; Nucleophilic additions; Macromolecules
1. Introduction
and stereochemistry of the resulting adducts. He also
reported that when the reaction takes place at room
temperature the only product obtained corresponds to
that from 3-addition giving, usually, the E isomer for
secondary and the Z isomer for primary amines. In a
related work, de Meijere [8] studied the influence of the
substitution of the triple bond on the stereochemistry of
the final adducts.
Recently, we have studied the reaction of bidentate
nucleophiles (amidines [9] and diamines [10]) with the
alkynyl alkoxy metal carbene complexes. The results
obtained in these studies, prompted us to explore more
deeply the possibilities of these systems towards the
synthesis of macrocyclic rings or macromolecular as-
semblies having metal carbene moieties. One of the
possibilities consists of the reaction of amines with the
aminocarbene alkynyl complexes. However, in a litera-
ture search, very few reports appear related to this
subject. In fact, to our knowledge, after the report of
Fischer on the substitution/addition of dimethylamine
on the alkynyl alkoxy carbenes, under different temper-
ature conditions, scarce information appears related to
these compounds. Do¨tz et al. [11] and Fischer [12]
reported the synthesis of related systems by using dif-
ferent synthetic pathways (alkynyl insertion).
Our current interest in polar acetylenic systems has
focused, for some time, on alkynyl alkoxy carbene
complexes, and different studies related to cycloaddi-
tions using these carbene complexes have been under-
taken by us [1]. In another line, we have studied the
reactivity of these complexes towards different nucleo-
philes [2] such as, alcohols, phenols, thiols and diphenyl
phosphine [3]. Also, Fischer and Aumann reported the
reactivity of the same systems towards carbanions [4]
and phosphines [5].
The presence of the metal carbonyl moiety enhances
the inherent reactivity of the triple bond and, therefore,
the addition of nucleophiles occurs under very mild
reaction conditions. The early work by Fischer on the
reaction of primary and secondary amines with alkynyl
alkoxy metal carbenes [6] revealed the importance of
the kinetic versus thermodynamic control in this reac-
tion and the influence brought about by the steric and
electronic effects in the regio (1-substitution versus
3-addition) and stereochemistry of the resulting product
mixture. A very extensive and complete work related to
this subject has been reported by Aumann [7], pointing
out the importance of the amine used either in the regio
We decided then to undertake a study related to the
addition of primary and secondary amines to different
mono, di and tri amino alkynyl metal carbene com-
* Corresponding author.
E-mail address: srmqob@cid.csic.es (S. Ricart).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(00)00636-7

J.M. Moreto´, S. Ricart / Journal of Organometallic Chemistry 617–618 (2001) 334–338
335
Table 1
Reaction of secondary amines with amino carbene complexes 1–3
Amine
Product (% yield) a
Fig. 1. Amino carbene complexes 1–3.
1
2
3
4
5
6
7
8
1a
1a
1b
1b
2
2
3
3
R¦ꢀR§ꢀallyl
R¦,R§ꢀ(CH2)5
R¦ꢀR§ꢀallyl
R¦ꢀMe, R§ꢀallyl
R¦ꢀR§ꢀallyl
R¦ꢀMe, R§ꢀallyl
R¦ꢀR§ꢀallyl
4a (67)
4b (72)
4c (70)
4d (65)
5a (75)
5b (80)
6a (60)
6b (50)
plexes (Fig. 1), with the purpose of obtaining com-
pounds by bearing, either, two nitrogen atoms with a
different reactivity pattern (possible access to hemi
labile ligands), or more complex structures with possi-
ble further application to the synthesis of macro-
molecules with metal carbene moieties.
R¦,R§ꢀ(CH2)5
a Reaction conditions: 0.1 M solution of the corresponding carbene
While complexes 1 and 2 have been previously de-
scribed [13] complex 3 was obtained by reaction of the
pentacarbonyl[(ethoxy)phenylethynyl]tungsten carbene
complex with the tris (2-aminoethyl)amine at −78°C in
a 0.3 M solution in dry THF. The reaction proceeded
in a stereoselective way affording as the major product
(more than 95% on the crude mixture) the one having
the E,E,E stereochemistry for the three carbene carbon
nitrogen bonds. This result is in close agreement with
that previously described from the reaction of primary
amines with alkynyl alkoxy carbene complexes [14].
in CH2Cl2, one equivalent of the corresponding amine; room temper-
ature; time: 18 h.
3. Reaction of complexes 1 and 2 with primary amines
The reaction of the corresponding alkynyl amino
mono and dicarbenes with primary amines took a
completely different path. In all the cases studied we
were not able to obtain the expected addition product,
but a mixture of compounds. This mixture changed
according to the elapsed reaction time, but remained
unaffected by changes in solvents (from THF to
CH2Cl2). We tried the reaction with the amino carbenes
1a, 1b and 2. In all cases the results were found the to
be same: decomposition of the original carbene moiety
to give instead a isocyanide complex of type 8.
2. Reaction of complexes 1, 2 and 3 with secondary
amines
The results obtained in the reaction of secondary
amines with complexes 1, 2 and 3 are described in
Table 1.
In all the cases, the addition was regio and stereose-
lective affording only the E isomer in accordance with
the results reported by Aumann for the addition of
similar amines on alkynyl alkoxy systems. To confirm
this assumption, we have performed the nOe experi-
ment of the complex 4a and the results obtained are
shown in the Fig. 2.
As an illustrative example, we show the case of
addition of allylamine to complex 1b. Although the
expected addition product was detected in the reaction
mixture after 1 h of reaction (a vinylic signal at ꢀ6.0
In the present cases, the reaction time is longer than
that described for the addition of the same amines on
the corresponding alkynyl alkoxy metal carbene com-
plexes. This is in good agreement with the decrease in
reactivity expected for the amino carbene systems, re-
lated to the oxy analogs.
Fig. 2. Results of the nuclear overhauser experiment with E-ua.
We have also studied the reaction of the carbene
complex 1b with N,N%-dimethylethylenediamine. The
reaction is shown in Scheme 1 and the corresponding
dicarbene complex 7 was obtained in moderate yield.
The study of the ring closing metathesis (RCM) to
afford the expected 15-member macrocycle is now in
progress [15].
Scheme 1. Reaction of N,N%-dimethylethylenediamine with complex
1b.

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J.M. Moreto´, S. Ricart / Journal of Organometallic Chemistry 617–618 (2001) 334–338
1
ppm was observed in the H-NMR spectrum), longer
reaction times afforded, as major products, the ones
corresponding to the structures 8 and 9. The formation
of these products could be accounted for by a 1,3-pro-
ton shift from the amines as shown in Scheme 2.
All attempts to isolate the addition product in the
early stages of the reaction failed and, from the chro-
matographic separation, we were able to obtain only
the isonitrile pentacarbonyl metal moiety 8 and ace-
tophenone 9, albeit in very low yields.
complexes were filtered through a pad of Celite and
EDTA prior to recording the spectra. IR spectra were
recorded on a Bomem FTIR M-120 spectrophotometer.
Mass spectra were obtained on an AutoSpec-Q mass
spectrometer. Elemental analyses were performed using
a Carlo Erba 1106 apparatus.
Flash column chromatography was performed with
‘flash grade’ silica (SDS 230–400 mesh).
Unless otherwise indicated all the reactions were
performed under Ar atmosphere. Carbene complexes
1a,b [13], and 2 [10] were prepared according to litera-
ture procedures.
This pattern presents some similarities with the ones
proposed by Aumann [16] and de Meijere [17] in the
case of addition of hydrazines and primary amines on
alkynyl alkoxy carbene systems.
5.1. Synthesis of triamino carbene complex 3
To a stirred solution of 0.482 g of pentacar-
bonyl[(ethoxy)phenylethynyl]tungsten carbene complex
(1 mmol) in 4 ml of dry THF at −78°C, 0.438 g of the
tris (2-aminoethyl)amine in (3 mmol) and 2 ml of THF
were added dropwise. The disappearance of the starting
compound was complete after 5 min of reaction (TLC).
The resulting mixture was evaporated and purification
by flash chromatography (hexane–CH2Cl2, 1:1) af-
forded 0.872 g of the compound 3 as an orange solid
(60% yield).
4. Conclusions
We present here a piece of work related to the
reactivity and possibilities of the alkynyl amino carbene
systems, on the way to the construction of more elabo-
rate molecules and macromolecules. We have shown
that the reactivity of these complexes towards amines
depends mainly on the use of primary or secondary
amines and, in the second case, new fairly stable and
easy to handle complexes were obtained. We also show
that primary amines did not give the expected com-
pounds. A mechanistic proposal is shown to explain
this abnormal behaviour. Further work related to this
subject is in progress in our laboratory.
5.1.1. Compound 3
1
IR (CHCl3) : 2167, 2063, 1978, 1942 cm−1. H-NMR
(CDCl3): l 3.05 (t, J=6.6 Hz, 6H, CH2); 3.84 (q,
J=6.6Hz, 6H, CH2); 7.35–7.55 (m, 15H, Ph); 8.89 (bs,
3H, NH). 13C-NMR (CDCl3): l 50.1 (t); 53.2 (t); 91.4
(s); 120.9 (s); 128.9 (d); 129.1 (s); 131.2 (d); 132.2 (d);
198.3 (s); 203.5 (s); 234.4 (CꢀW). MS (FAB+, matrix
NBA) 1454 (M+), 1342, 1314, 1286, 1258, 1034, 850.
Anal. Calc. for C48H30N4O15W3: C, 39.61; H, 2.06; N,
3.85. Found: C, 39.39; H, 2.02; N, 3.87%.
5. Experimental
Unless otherwise stated all common reagents and
solvents were used as obtained from commercial suppli-
ers without further purification.
NMR spectra were recorded on a Varian Gemini-200
5.2. General procedure for the reaction with secondary
amines
1
(200 MHz for H-NMR and 50 MHz for 13C-NMR) or
1
a Varian XL-300 apparatus (300 MHz for H-NMR
and 75.4 MHz for 13C-NMR). All samples of carbene
To a stirred 0.1 M solution of the carbene in CH2Cl2
at room temperature (r.t.), one equivalent of the amine
was added. The reaction course was monitored by
TLC. After the starting carbene complex had com-
pletely disappeared, the solvent was removed and the
residue passed through
column.
a
flash chromatography
5.3. Synthesis of compound 4a
The reaction was performed using 0.247 g (0.5 mmol)
of 1a and 0.049 g (0.5 mmol) of the diallyl amine in 4
ml of CH2Cl2. After purification by flash chromatogra-
phy (hexane–CH2Cl2, 1:1), 0.198 g of complex 4a was
obtained as a yellow solid (67% yield).
Scheme 2. Reaction of allylamine with complex 1b.

J.M. Moreto´, S. Ricart / Journal of Organometallic Chemistry 617–618 (2001) 334–338
337
5.3.1. Compound 4a
5.69–5.75 (m, 1H, CH); 6.16 (s, 1H, CH); 6.90 (bs, 1H,
NH); 7.20–7.50 (m, 5H, Ph). 13C-NMR (CDCl3): l
37.8 (q); 54.4 (t); 57.3 (t); 117.9 (t); 118.3 (t); 118.9 (d);
129.2 (d); 129.3 (d); 129.4 (d); 131.9 (d); 132.6 (d); 135.0
(s); 148.8 (s); 199.4 (s); 204.2 (s); 238.2 (CꢀW).
IR (CHCl3): 2063, 1978, 1942 cm−1
.
1H-NMR
(CDCl3): l 0.65 (t, J=10.8 Hz, 3H, CH3); 0.94 (dq,
J=10.2, 10.8 Hz, 2H, CH2); 3.27 (dt, J=10.2, 10.8 Hz,
2H, CH2); 3.67 (d, J=7.8 Hz, 2H, CH2); 5.10–5.27 (m,
2H, CH2); 5.64–5.89 (m, 1H, CH); 6.24 (s, 1H, CH);
7.01 (bs, 1H, NH); 7.20–7.50 (m, 5H, Ph. 13C-NMR
(CDCl3): l 11.0 (q); 22.0 (t); 51.6 (t); 56.3 (t); 117.9 (t);
118.5 (d); 129.3 (d); 129.4 (d); 129.5 (d); 132.5 (d); 135.2
(s); 147.4 (s); 199.5 (s); 204.3 (s); 237.1 (CꢀW).
5.7. Synthesis of compound 5a
The reaction was performed using 0.466 g (0.5 mmol)
of 2 and 0.097 g (1 mmol) of the diallyl amine in 4 ml
of CH2Cl2. After purification by flash chromatography
(hexane–CH2Cl2, 1:2), 0.422 g of complex 5a was ob-
tained as a yellow solid (75%).
5.4. Synthesis of compound 4b
The reaction was performed using 0.250 g (0.5 mmol)
of 1a and pyperidine 0.043 g (0.5 mmol) in 4 ml of
CH2Cl2. After purification by flash chromatography,
0.208 g of complex 4b was obtained as a yellow solid.
(72%).
5.7.1. Compound 5a
IR (CHCl3): 2055, 1953, 1897 cm−1
.
1H-NMR
(CDCl3): l 2.85 (bs, 4H, CH2); 3.68 (bs, 8H, CH2); 5.10
(d, J=10.8 Hz, 4H, CH2); 5.30 (d, J=17 Hz, 4H,
CH2); 5.70 (ddd, J=6.9, 10.8, 17 Hz, 4H, CH); 6.23 (s,
2H, CH); 6.90 (bs, 2H, NH); 7.10–7.20 (m, 4H, Ph);
7.40–7.60 (m, 6H, Ph). 13C-NMR (CDCl3): l 51.6 (t);
52.7 (t); 117.8 (d); 118.0 (t); 128.8 (d); 129.6 (d); 130.2
(d); 132.2 (d); 134.5 (s); 148.9 (s); 199.4 (s); 203.8 (s);
238.8 (CꢀW).
5.4.1. Compound 4b
IR (CHCl3): 2069, 1984, 1942 cm−1
.
1H-NMR
(CDCl3): l 0.60 (t, J=10.8 Hz, 3H, CH3); 0.90–1.05
(m, 2H, CH2); 1.60 (bs, 6H, CH2); 2.95 (bs, 4H, CH2);
3.2 (m, 2H, CH2); 6.12 (s, 1H, CH); 7.11 (bs, 1H, NH);
7.20–7.50 (m, 5H, Ph).
5.8. Synthesis of compound 5b
5.5. Synthesis of compound 4c
The reaction was performed using 0.466 g (0.5 mmol)
of 2 and 0.071 g (1 mmol) of allyl methyl amine in 4 ml
of CH2Cl2. After purification by flash chromatography
(hexane–CH2Cl2, 1:2), 0.430 g of complex 5b was ob-
tained as a yellow solid (80%).
The reaction was performed using 0.250 g (0.5 mmol)
of 1b and 0.050 g (0.5 mmol) of diallyl amine in 4 ml of
CH2Cl2. After purification by flash chromatography
(CH2Cl2), 0.206 g of complex 4c was obtained as a
yellow solid (70% yield).
5.8.1. Compound 5b
5.5.1. Compound 4c
IR (CHCl3): 2053, 1955, 1907 cm−1 1H-NMR
.
IR (CHCl3): 2055, 1932, 1912 cm−1
.
1H-NMR
(CDCl3): l 2.61 (s, 6H, CH3); 3.00 (bs, 4H, CH2); 3.91
(t, J=6 Hz, 4H CH2); 4.95 (dd, J=10.6, 17 Hz, 4H,
CH2); 5.21 (ddd, J=6, 10.6, 17 Hz, 4H, CH); 6.04 (s,
2H, CH); 6.29 (bs, 2H, NH); 7.10–7.20 (m, 4H, Ph);
7.40–7.60 (m, 6H, Ph). 13C-NMR (CDCl3): l 38.4 (t);
48.9 (t); 67.3 (t); 118.7 (d); 119.1 (t); 129.2 (d); 129.5 (d);
131.6 (d); 134.5 (d); 147.6 (s); 199.3 (s); 203.9 (s); 238.8
(CꢀW).
(CDCl3): l 3.69 (d, J=4.5 Hz, 4H, CH2); 3.92 (d, J=6
Hz, 2H, CH2); 5.00–5.27 (m, 6H, CH2); 5.70–5.80 (m,
3H, CH); 6.27 (s, 1H, CH); 6.92 (bs, 1H, NH); 7.20–
7.50 (m, 5H, Ph). 13C-NMR (CDCl3): l 51.7 (t); 57.4
(t); 117.9 (t); 118.3 (d); 118.9 (t); 129.2 (d); 129.3 (d);
129.5 (d); 131.9 (d); 132.5 (d); 135.0 (s); 148.0 (s); 199.4
(s); 204.2 (s); 238.0 (CꢀW).
5.6. Synthesis of compound 4d
5.9. Synthesis of compound 6a
The reaction was performed using 0.250 g (0.5 mmol)
of 1b and 0.040 g (0.5 mmol) of methyl allyl amine in 4
ml of CH2Cl2. After purification by flash chromatogra-
phy (hexane–CH2Cl2, 1:1), 0.183 g of complex 4d was
obtained as a yellow solid (65%).
The reaction was performed using 0.485 g (0.3 mmol)
of 3 and 0.088 g (0.9 mmol) of the diallyl amine in 4 ml
of CH2Cl2. After purification by flash chromatography
(CH2Cl2), 0.307 g of complex 6a was obtained as a
yellow solid (60%).
5.6.1. Compound 4d
5.9.1. Compound 6a
IR (CHCl3): 2055, 1978, 1905 cm−1
.
1H-NMR
IR (CHCl3): 2055, 1955, 1907 cm−1 1H-NMR
.
(CDCl3): l 3.54 (d, J=5.4 Hz, 2H, CH2); 3.92 (t,
J=5.7 Hz, 2H, CH2); 4.80–5.35 (m, 5H, CH, CH2);
(CDCl3): l 1.72 (bt, 6H, CH2); 3.13 (bq, 6H, CH2); 3.70
(bs, 12H, CH2); 5.25 (d, J=17.4Hz, 6H, CH2); 5.27 (d,

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J.M. Moreto´, S. Ricart / Journal of Organometallic Chemistry 617–618 (2001) 334–338
J=10.2 Hz, 6H, CH2); 5.70 (ddd, J=6, 10.2, 17.4 Hz,
6H, CH); 6.25 (s, 3H, CH); 6.82 (bs, 3H, NH); 7.10–
7.30 (m, 6H, Ph); 7.40–7.60 (m, 9H, Ph). 13C-NMR
(CDCl3): l 51.0 (t); 51.2 (t); 51.7 (t); 118.0 (s); 118.4 (t);
129.3 (d); 129.4 (d); 129.5 (d); 132.3 (d); 135.1 (s); 148.2
(s); 199.6 (s); 203.9 (s); 238.1 (CꢀW).
yield) and 0.020 g of acetophenone 9 (24% yield) were
obtained.
5.12.1. Compound 8a
IR (CHCl3): 2178, 2069, 1950 cm−1
.
1H-NMR
(CDCl3): l 4.33 (bs, 2H, CH2); 5.30–5.50 (m, 2H,
CH2); 5.70–6.00 (m, 1H, CH). 13C-NMR (CDCl3): l
46.5 (t); 118.5 (t); 128.0 (d); 194.2 (s); 196.2 (s); (NC)
not found.
5.10. Synthesis of compound 6b
The reaction was performed using 0.485 g (0.3 mmol)
of 3 and 0.064 g (0.9 mmol) of pyperidine in 4 ml of
CH2Cl2. After purification by flash chromatography
(CH2Cl2), 0.252 g of complex 6b was obtained as a
yellow solid (50%).
Acknowledgements
The authors acknowledge the financial support from
DGICYT (PB-94-0084). We thank Nuria Bejar and
Daniel Font for his helpful assistance.
5.10.1. Compound 6b
IR (CHCl3): 2067, 1947, 1935 cm−1
.
1H-NMR
References
(CDCl3): l 1.62 (bs, 24h, CH2); 1.72 (bt, 6H, CH2); 3.02
(bs, 12H, CH2); 3.13 (bq, 6H, CH2); 6.13 (s, 3H, CH);
6.87 (bs, 3H, NH); 7.10–7.30 (m, 6H, Ph); 7.40–7.60
(m, 9H, Ph). 13C-NMR (CDCl3): l 24.2 (t) 25.4 (t), 49.4
(t); 50.9 (t); 119.74 (d); 129.2 (d); 129.6 (d); 135.6 (s);
149.5 (s); 199.5 (s); 203.9 (s); 238.9 (CꢀW).
[1] (a) F. Camps, J.M. Moreto´, S. Ricart, J.M. Vin˜as, Angew.
Chem. Int. Ed. Engl. 30 (1991) 1470. (b) L. Jordi, J.M. Vin˜as, S.
Ricart, J.M. Moreto´, Organometallics, 16 (1997) 2808.
[2] (a) For a recent review on this subject: R. Aumann, H. Nien-
naber, Adv. Organomet. Chem. 41 (1997) 163. (b) F. Camps, A.
Llebaria, J.M. Moreto´, S. Ricart, J. Ros, J.M. Vin˜as, J.
Organomet. Chem. 401 (1991) C-17.
5.11. Synthesis of compound 7
[3] A. Llebaria, J.M. Moreto´, S. Ricart, J. Ros, J.M. Vin˜as, R.
Yan˜ez, J. Organomet. Chem. 440 (1992) 79.
The reaction was performed using 0.250 g (0.5 mmol)
of 1b and 0.022 g (0.25 mmol) of N,N%-dimethyl-
ethylenediamine in 4 ml of CH2Cl2. After purification
by flash chromatography (hexane–CH2Cl2, 1:1), 0.175
g of complex 7 was obtained as an orange solid (30%).
[4] H. Fischer, T. Meisner, J. Hofmann, Chem. Ber. 123 (1990)
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[7] (a) R. Aumann, P. Hinterding, Chem. Ber. 126 (1993) 421. (b) R.
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454 (1993) 133.
5.11.1. Compound 7
IR (CHCl3): 2051, 1955, 1887 cm−1
.
1H-NMR
(CDCl3): l 3.02 (s, 6H, CH3); 3.00 (bs, 4H, CH2); 3.70
(bs, 4H, CH2); 4.88 (d, J=18Hz, 2H, CH2); 4.97 (d,
J=10.2Hz, 2H, CH2); 5.21 (ddd, J=6, 10.2, 18 Hz,
2H, CH); 6.04 (s, 2H, CH); 6.87 (bs, 2H, NH); 7.10–
7.30 (m, 4H, Ph); 7.40–7.60 (m, 6H, Ph). 13C-NMR
(CDCl3): l 38.4 (q) 48.9 (t); 57.3 (t); 118.7 (d); 119.1 (t);
129.2 (d); 129.5 (d); 131.6 (d); 134.5 (s); 147.6 (s); 199.3
(s); 203.9 (s); 238.8 (CꢀW).
[13] J. Pares, J.M. Moreto´, S. Ricart, J. Barluenga, F.J. Fan˜anas, J.
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5.12. Reaction with primary amines. Reaction of 1b
with allyl amine
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[15] As part of a joint project with the University of Bonn, Germany.
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2445.
[17] M. Duetsch, F. Stein, F. Funke, E. Pohl, R. Herbst-Irmer, A. de
Meijere, Chem. Ber. 126 (1993) 2535.
The reaction was performed using 0.350 g (0.7 mmol)
of 1b and 0.040 g (0.7 mmol) of allylamine in 2 ml of
CH2Cl2 at r.t. After purification by flash chromatogra-
phy (hexane–CH2Cl2, 1:1), 0.040 g of complex 8a (15%
.