Reactivity of dimetallapentaboranes-nido- [Cp2*M2B3H7]-with alkynes: Insertion to form a ruthenacarborane (M = RuH) versus catalytic cyclotrimerization to form arenes (M = Rh)

Article abstract of DOI:10.1002/1521-3773(20011203)40:23<4498::AID-ANIE4498>3.0.CO;2-3

Catalysis with clusters: Transition metal characteristics control metallaborane reactivity as demonstrated by the reaction of a pair of isoelectronic and nearly isostructural metallaboranes with substituted alkynes. Novel catalytic chemistry of nido-[1,2-(Cp*Rh)₂B₃H₇] and nido-[2,3-(Cp*Rh)₂B₃H₇] (shown) with alkynes (see scheme) is observed with activities and selectivities that depend on catalyst structure and the alkyne substituents.

Full text of DOI:10.1002/1521-3773(20011203)40:23<4498::AID-ANIE4498>3.0.CO;2-3

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Zhang, Org. Lett. 1999, 1, 1287 1290; f) B. Lygo, D. C. M. To,
Tetrahedron Lett. 2001, 42, 1343 1346.
[13] M. B. Hursthouse, M. E. Light, S. J. Coles, Department of Chemistry,
University of Southampton, personal communication.
The chemistry of [1,2-(Cp*RuH)2B3H7] (1; Cp* ˆ C5Me5),
has been explored by our group[8] and that of Shimoi.[17 19] The
results pertinent to this work are shown in Scheme 1 and
illustrate a) cluster expansion and b) cluster degradation.
Reaction of 1 with HCCCO2Me leads to [1,2-(Cp*RuH)2-
3,4-CHC(CO2Me)B2H4] (2; Figure 1),[20] which results from
combined cluster degradation and expansion (path c in
Reactivity of Dimetallapentaboranes–nido-
*
[Cp2 M2B3H7]–with Alkynes: Insertion to
Form a Ruthenacarborane (M ˆ RuH) versus
Catalytic Cyclotrimerization to Form Arenes
(M ˆ Rh)**
Hong Yan, Alicia M. Beatty, and Thomas P. Fehlner*
A significant fraction of modern chemistry incorporates the
use of transition metals to modify and control the reactivity of
main group moieties, for example, organometallic chemistry,
and the use of ligands to modify and control the reactivity at
metal sites, for example, supramolecular chemistry. Relative
to the other p-block elements, the chemistry of carbon is
dominant, however, in principle, a similar wealth of chemistry
exists for the other p-block elements.[1] In fact, transition
metal promoted main group chemistry[2] and main group
element promoted transition metal chemistry[3] has generated
more interest recently.
Since developing a practical synthetic route to a class of
metallaboranes containing metals ranging from Group 5 9,[4]
we have begun to examine the systematic reaction chemistry
of these compounds. Thus, thermal elimination reactions as
well as reactions with metal fragments, monoboranes, and
Scheme 1. Reactions of 1 with a) monoborane to give cluster expansion,
b) with PMe3 to give cluster degradation, and c) with HCCCO2Me to yield
2. The structures shown are schematic representations, for clarity only the
*
H-bridge of the H-bridged bonds is shown, ˆ H.
11]
Lewis bases have been described.[5 In these reactions, the
distinctive electronic contributions of metal and borane
fragments to the cluster structure are seen to be expressed
in the overall reactivity. In one case, a new class of metalla-
borane was revealed, the hypoelectronic rhenaboranes.[12]
In the early days of organometallic chemistry, the reaction
of metal species with alkynes yielded a wealth of compounds
that helped define structural possibilities.[13] Likewise, the
reaction of alkynes with boranes gave rise to carboranes[14]
and a subsequent bountiful chemistry of these heteroboranes
with metals[15] including catalytic applications.[16] Here we
report the comparative reactivity of two isoelectronic nido-
dimetallapentaboranes with alkynes and demonstrate that a
change from Group 8 to Group 9 metal drives a change in the
reaction from alkyne insertion to catalytic cyclotrimerization.
The latter reaction shows that, with the proper choice of
metal, metallaborane clusters provide access to a novel
catalytic pathway.
À
Figure 1. Molecular structure of 2. Selected bond lengths [ä]: Ru1 Ru2
À
À
À
2.9424(10), Ru1 C1 2.170(8), Ru1 C2 2.180(8), Ru1 B1 2.358(10),
À
À
À
À
Ru1 B2 2.360(10), Ru2 B2 2.385(10), Ru2 B1 2.399(10), B1 C1
À
À
À
À
1.508(14), B2 C2 1.557(13), C1 C2 1.391(12), C2 C3 1.493(12), O1 C3
[*] Prof. T. P. Fehlner, Dr. H. Yan, Dr. A. M. Beatty
Department of Chemistry and Biochemistry
University of Notre Dame
À
À
1.352(11), O1 C4 1.448(11), O2 C3 1.208(11).
Notre Dame, IN 46556 (USA)
Scheme 1). This reaction is analogous to the reaction of 1 with
phosphanes except that ultimately the alkyne base is incorpo-
rated into the borane framework rather than coordinated to a
metal site. Thermal reaction of metallaboranes with alkynes
Fax : (‡1)219-631-6652
E-mail: fehlner.1@nd.edu
[**] This work was supported by the National Science Foundation. Cp* ˆ
h-C5Me5.
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to form metallacarboranes is known[21, 22] as is the metal-
catalyzed formation of polyhedral vinyl boranes, which can be
precursors to carboranes.[23]
Rh
The synthesis of [2,3-(Cp*Rh)2B3H7] (4) has been report-
ed.[8, 24] Further work has led to the isolation of [1,2-
(Cp*Rh)2B3H7] (3; Figure 2)[20] which cleanly converts into 4
on heating. As illustrated in Scheme 2, 3 exists in solution as a
equilibrium mixture of two tautomers that differ solely in the
placement of one endo hydrogen atom. Isomer 3a, a direct
analogue of B5H9, has an RhHB bridge (abundance 40%)
whereas 3b has a structurally unusual apical basal RhHRh
bridge (abundance 60%).
B
B
Rh
B
Rh
B
3b
B
B
Rh
B
Rh
B
Rh
Rh
4
B
B
Rh
B
3a
Scheme 2. Formation of 4, from [(Cp*Rh)2B2H6] and monoboranes via the
intermediate 3 which exists in two tautomeric forms in solution.
degradation. Partial inhibition of the catalysis by triphenyl-
phosphane and pyridine, neither of which degrades the
rhodaboranes under the reaction conditions, suggests com-
petition between the alkyne and added Lewis base for the
active site on the rhodaborane.
In contrast to, for example, 16 electron rhodium cyclo-
trimerization catalysts containing chelating carborane li-
gands,[25] compounds 3 and 4 are formally saturated and have
no labile ligands. Hence, the observed catalytic activity may
seem puzzling, however, cluster species of this type are
intrinsically Lewis acidic relative to non-cluster compounds
with saturated electronic structures. Both base-catalyzed
framework rearrangements in pentaborane(9)[26, 27] and ligand
substitutions in a metal cluster[28] involve addition of a base to
open the cluster thereby facilitating rearrangement before
base dissociation and cluster closing. Incorporation of this
cluster ™breathing∫ process into the ™common∫ mechanism
for alkyne cyclotrimerization[29] leads to a reasonable catalytic
cycle shown in abbreviated form for 4 (3 exists as two
tautomers each with two different metal sites) in Scheme 3.
The presence of two Cp*RuH fragments in a pentaborane
cluster framework leads to insertion whereas Cp*Rh frag-
ments generate catalytic cyclotrimerization. Catalysis by
clusters has been an attractive area since its inception[30] but
one that has often been frustrated by facile cluster degrada-
tion.[31] A metallaborane is electronically, as well as geometri-
cally, similar to a metal cluster of the same nuclearity. Thus,
the borane fragment supports the metal atoms in a cluster
environment and provides a reaction pathway not available
to, for example, an 18 electron organometallic complex.
À
Figure 2. Molecular structure of 3a. Selected bond lengths [ä]: Rh1 Rh2
À
À
À
À
2.6892(3), Rh1 B3 2.292(4), Rh1 B1 2.308(3), Rh2 B2 2.061(4), Rh2 B1
À
À
À
2.062(3), Rh2 B3 2.075(4), B1 B2 1.841(5), B2 B3 1.838(5).
The net result of the reaction of either 3 or 4 with a selection
of alkynes (Table 1) is the formation of mixtures of 1,2,4- and
1,3,5-substituted benzenes without observable degradation of
the rhodaborane. Rates and turnover numbers are modest.
ꢀ
Decreasing activities for RC CPh, R ˆ H, Me, Ph, suggest a
significant steric factor in the reaction. Comparison of rates
for HCCCO2Me, catalyzed by 3 and 4 under identical
conditions, establishes that 3 is ꢁ6 times more active at room
temperature. The difference in selectivity between 3 and 4
ꢀ
(compare MeC CR, R ˆ Ph vs CO2Me) supports catalysis by
the rhodaboranes rather than by a fragment derived from
Table 1. Comparison of selected catalytic data.[a]
Substrate
3[a]
T [8C]
4[a]
T [8C]
Cat:substrate
t [h]
yield [%] product ratio
Cat:substrate
24 22
t [h]
yield [%] product ratio
1:4
ꢀ
HC CPh
1:143
1:84
1:12
1:77
1:100
24
70
48
48
68
22
22
22
22
22
271:3
3
1:36
39
[b]
[b]
ꢀ
MeC CPh
1:70
24
36
24
24
70
70
47
65
36
ꢀ
PhC CPh
NR
85
22
1:10
1:260
1:70
NR
ꢀ
HC CCO2Me
1:3
1:1
42
10
1:5
3:1
ꢀ
MeC CCO2Me
[a] Catalyst to substrate ratio, reaction time, reaction temperature, total yield, ratio of 1,3,5- to 1,2,4-trisubstituted benzene, NR ˆ no reaction. [b] 1,2,4-
trimethyl-3,5,6-triphenylbenzene only.
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[1] Inorganometallic Chemistry (Ed.: T. P. Fehlner), Plenum, New York,
1992.
B
[2] H. Chen, S. Schlecht, T. C. Semple, J. F. Hartwig, Science 2000, 287,
1995.
[3] H. Tobita, K. Hasegawa, J. J. G. Minglana, L.-S. Luh, M. Okazaki, H.
Ogino, Organometallics 1999, 18, 2058.
B
Rh
B
a
Rh
[4] T. P. Fehlner, Organometallics 2000, 19, 2643.
[5] J. Ho, K. J. Deck, Y. Nishihara, M. Shang, T. P. Fehlner, J. Am. Chem.
Soc. 1995, 117, 10292.
[6] H. Hashimoto, M. Shang, T. P. Fehlner, Organometallics 1996, 15,
1963.
[7] S. Aldridge, H. Hashimoto, K. Kawamura, M. Shang, T. P. Fehlner,
Inorg. Chem. 1998, 37, 928.
B
B
b
B
Rh
Rh
B
4
[8] X. Lei, M. Shang, T. P. Fehlner, J. Am. Chem. Soc. 1999, 121, 1275.
[9] X. Lei, M. Shang, T. P. Fehlner, Chem. Eur. J. 2000, 6, 2653.
[10] S. Ghosh, X. Lei, M. Shang, T. P. Fehlner, Inorg. Chem. 2000, 39, 5373.
[11] X. Lei, M. Shang, T. P. Fehlner, Organometallics 2000, 19, 5266.
[12] S. Ghosh, M. Shang, Y. Li, T. P. Fehlner, Angew. Chem. 2001, 113,
1159; Angew. Chem. Int. Ed. 2001, 40, 1125.
B
Rh
B
Rh
c
[13] C. Elschenbroich, A. Salzer, Organometallics, VCH, New York, 1989.
[14] R. N. Grimes, Carboranes, Academic Press, New York, 1970.
[15] M. F. Hawthorne, J. Organomet. Chem. 1975, 100, 97 .
[16] R. T. Baker, M. S. Delaney, R. E. King III, C. B. Knobler, J. A. Long,
T. B. Marder, T. E. Paxson, R. G. Teller, M. F. Hawthorne, J. Am.
Chem. Soc. 1984, 106, 2965.
[17] Y. Kawano, H. Matsumoto, M. Shimoi, Chem. Lett. 1999, 489.
[18] L. N. Pangan, Y. Kawano, M. Shimoi, Organometallics 2000, 19, 5575.
[19] L. N. Pangan, Y. Kawano, M. Shimoi, Inorg. Chem. 2001, 40, 1985.
[20] Crystallographic data (excluding structure factors) for the structures
reported in this paper have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publication
no. CCDC-168355 (2) and -168356 (3). Copies of the data can be
obtained free of charge on application to CCDC, 12 Union Road,
Cambridge CB21EZ, UK (fax: (‡44)1223-336-033; e-mail: deposit@
ccdc.cam.ac.uk).
[21] R. Weiss, J. R. Bowser, R. N. Grimes, Inorg. Chem. 1978, 17, 1522.
[22] E. J. Ditzel, X. L. R. Fontaine, N. N. Greenwood, J. D. Kennedy, Z.
Sisan, B. Stibr, M. Thornton-Pett, J. Chem. Soc. Chem. Commun. 1990,
1741.
[23] R. Wilczynski, L. G. Sneddon, Inorg. Chem. 1982, 21, 506.
[24] X. Lei, M. Shang, T. P. Fehlner, J. Am. Chem. Soc. 1998, 120, 2686.
[25] M. Herberhold, H. Yan, W. Milius, B. Warckmeyer, Organometallics
2000, 19, 4289.
Scheme 3. Proposed catalytic cycle for the cyclotrimerization of alkynes
by 4.
Experimental Section
2: [1,2-(Cp*RuH)2B3H7] (125 mg, 0.24 mmol)[8] in hexane(20 mL) and
methyl acetylene monocarboxylate (0.2 mL, 2.24 mmol) were stirred for
8 h at ambient temperature. A yellow solid formed and the suspension
became orange. The reaction mixture was concentrated and chromatog-
raphy (silica gel 60 200) with hexane:toluene ˆ 10:1 afforded the known
nido cluster [1,2-(Cp*Ru)2(m-H)B4H9] (8.6 mg, 7%) and with hexane:ether
(10:1) the yellow [1,2-(Cp*RuH)2-3,4-CHC(CO2Me)B2H4] (2; 74.4 mg,
1
53%): H NMR ([D6]benzene, 228C, 600 MHz): d ˆ 5.53 (s, br, 1H, CH),
3.58 (s, 3H, OMe), 2.72 (br, 2H, B-Ht), 1.78 (s, 15H, Cp*), 1.74 (s, 15H,
Cp*), À 11.59 (s, 1H, Ru-H-Ru), À11.69 (s, 1H, Ru-H-Ru), À12.25 (s, br,
1H, Ru-H-B), À12.42 (s, br, 1H, Ru-H-B); 11B NMR ([D6]acetone, 228C,
128 MHz): d ˆ À14.2, À15.2 (1:1); 13C NMR ([D6]acetone, 228C,
ˆ
ˆ
125 MHz): d ˆ 175.4 (CO), 124.9 (br, C CH), 96.6 (br, C CH), 93.4
(Cp*), 88.8 (Cp*), 50.8 (OMe), 12.1 (Cp*), 10.8 (Cp*); EI-MS: 586.1290
‡
(M , found), 586.1297(calcd); IR (KBr): nÄ ˆ 2468(nBÀH), 1604, 1373, and
1222(nCOOÀ1) cmÀ1
.
3: LiBH4 (0.45 mL, 0.90 mmol) was added to a stirred orange suspension of
[Cp*RhCl2]2 (100 mg, 0.16 mmol) in THF (20 mL) at À208C. The release
of H2 accompanied the formation of a yellow solution (ca. 0.5 h) which was
warmed to room temperature for 0.5 h and then heated to 708C for 6.5 h.
After removal of solvent, the residue was dissolved in hexane and applied
to a silica gel column (2 Â 10 cm). Elution with hexane:toluene (10:1) gave
a red band which contained an inseparable 1:1.25 mixture of nido-[-1,2-
(Cp*Rh)2B3H7] (3a) and nido-[-1,2-(Cp*Rh)2(m-H)B3H6] (3b; 30.5 mg,
37% based on Rh). Further elution with hexane:toluene (1:1) afforded 4
[26] D. F. Gaines, Acc. Chem. Res. 1973, 6, 416.
[27] D. F. Gaines in Boron Chemistry-4 (Eds: R. W. Parry, G. Kodama),
Pergamon, Oxford, 1980, p. 7 3.
[28] K. Knoll, G. Huttner, L. Zsolnai, I. Jibril, M. Wasincionek, J.
Organomet. Chem. 1985, 294, 91.
[29] N. E. Schore, Chem. Rev. 1988, 88, 1081.
[30] E. L. Muetterties, T. N. Rhodin, E. Band, C. F. Brucker, W. R. Pretzer,
Chem. Rev. 1979, 79, 91.
[31] W. L. Gladfelter, K. J. Roesselet in The Chemistry of Metal Cluster
Complexes (Eds: D. F. Shriver, H. D. Kaesz, R. D. Adams), VCH,
New York, 1990, p. 329.
1
(21.4 mg, 26% based on Rh): H NMR ([D6]benzene, À608C, 400 MHz):
3a: d ˆ 3.95 (br, 1H, B-Ht), 3.66 (br, 2H, B-Ht), 2.07(s, 15H, Cp*), 1.53 (s,
15H, Cp*), À3.05 (s, 2H, B-H-B), À12.04 (s, 2H, B-H-Rh); 3b: 5.72 (br,
1H, B-Ht), 4.19 (br, 1H, B-Ht), 2.73 (br, 1H, B-Ht), 1.94 (s, 15H, Cp*), 1.70
(s, 15H, Cp*), À0.16 (s,1H, B-H-B), À3.35 (s, 1H, B-H-B), À14.54 (s, 1H,
B-H-Rh), À15.04 (dd, J1 ˆ 22.1 Hz, J2 ˆ 28.3 Hz, 1H, Rh-H-Rh); 11B
([D6]benzene, 228C, 128 MHz): d ˆ 5.66, 8.17, 11.02, 22.34 (br); EI-MS:
‡
516.1304 (M , 100%, found), 516.1272 (calcd).
Catalytic reactions: In a typical reaction, 4 (8 mg, 15.5 Â 10À3 mmol) was
dissolved in THF (15 mL) and methyl acetylene monocarboxylate
(0.36 mL, 4.04 mmol) was added. The resulting reaction mixture was
stirred at room temperature for 24 h gradually generating a white solid on
the flask wall. After removal of solvent, the residue was purified by
chromatography on silica gel. Elution with hexane:CH2Cl2 (3:1) gave 4
(5 mg) and elution with acetone gave a 5:1 mixture of 1,2,4-and 1,3,5-
trimethylbenzenetricarboxylates (142.5 mg, 42%). Data on the trimers (1H,
13C NMR spectroscopy, high resolution mass spectroscopy) corresponded
to published spectra.
Received: August 16, 2001 [Z17738]
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(h3-Allyl)palladium Complexes Bearing
Diphosphinidenecyclobutene Ligands:
Highly Active Catalysts for the
R
R
+
Ar
P
OTf–
Pd
Hydroamination of 1,3-Dienes**
P
Tatsuya Minami, Hideyuki Okamoto, Shintaro Ikeda,
Rika Tanaka, Fumiyuki Ozawa,* and Masaaki Yoshifuji
Ar
Ar = 2,4,6-tri-tert-butylphenyl
1: R = H; 2: R = OMe; 3: R = CF3
Dedicated to Prof. FranÁoisMathey
on the occasion of his 60th birthday
(AgOTf) in CH2Cl2 at room temperature, and isolated as
yellowish orange solids in 66 96% yields.[14] They are fairly
stable towards air in solution and as solids; the solid materials
can be stored at room temperature for months without
notable decomposition.
Figure 1 shows the molecular structure of 1.[15] The diphos-
phinidenecyclobutene ligand chelates the (h3-allyl)palladium
The catalytic hydroamination of unsaturated hydrocarbons
is a useful means of synthesizing nitrogen-containing organic
molecules.[1] Intramolecular cyclization of aminoalkenes is
efficiently catalyzed by lanthanide complexes,[2] and amine-
induced telomerization of butadienes[3] and oxidative 1,4-
addition of amines to dienes[4] are successfully conducted with
palladium catalysts. In contrast, simple intermolecular 1:1
addition of amines to alkenes or dienes is a rather difficult
process and has been conducted at high temperature.[5, 6]
Hartwig et al. recently reported a significantly improved
catalyst, generated from [Pd(PPh3)4] and CF3CO2H, which
performs 1:1 addition of aniline to 1,3-dienes at room
temperature.[7] However, even in this case, the reaction takes
about a day for completion. Here we report that more
efficient catalysts can be prepared by using sp2-hybridized
phosphorus ligands, namely, 1,2-diaryl-3,4-bis[(2,4,6-tri-tert-
butylphenyl)phosphinidene]cyclobutenes.[8]
Figure 1. Molecular structure of the cation in crystals of 1 ¥ 2C6H6.
Thermal ellipsoids are drawn at the 30% probability level. Triflate anion,
benzene molecules (solvent of crystallization), and hydrogen atoms are
omitted for clarity. Selected bond lengths [ä] and angles [8]: Pd-P(1)
2.326(1), Pd-P(2) 2.322(1), Pd-C(53) 2.168(5), Pd-C(54) 2.168(5), Pd-C(55)
2.178(4), P(1)-C(19) 1.667(4), P(2)-C(22) 1.671(4), C(19)-C(20) 1.476(5),
C(19)-C(22) 1.499(5), C(20)-C(21) 1.406(5), C(21)-C(22) 1.464(5), C(53)-
C(54) 1.383(8), C(54)-C(55) 1.376(8); P(1)-Pd-P(2) 85.50(4), Pd-P(1)-C(19)
107.6(1), Pd-P(2)-C(22) 107.4(1), P(1)-C(19)-C(22) 119.6(3), C(20)-C(19)-
C(22) 87.8(2), P(2)-C(22)-C(19) 119.9(3), C(19)-C(22)-C(21) 88.5(3),
C(19)-C(20)-C(21) 91.7(3), C(20)-C(21)-C(22) 91.9(3), C(53)-C(54)-C(55)
119.9(5). Dihedral angles between least-squares planes [8]: [A]-[B] 2.3(1),
[A]-[C] 93.2(1), [A]-[D] 100.3(1), [B]-[E] 28.2(2), [B]-[F] 147.8(2).
sp2-Hybridized phosphorus compounds have a marked
propensity to engage in metal-to-phosphorus p backbonding
and have a strong p-acceptor property, comparable to that of
the carbonyl ligand.[9] Since the catalytic addition of an amine
to a 1,3-diene probably involves nucleophilic attack of the
amine on an (h3-allyl)palladium(ii) or palladium(ii) diene
complex,[7a] we expected that diphosphinidenecyclobutene
ligands may effectively enhance the electrophilicity of palla-
dium intermediates and thus give highly active catalysts.
Although transition metal complexes of sp2-hybridized phos-
phorus compounds have been extensively prepared in the last
decade,[9] their application to catalysis has been extremely
limited,[10] except for phosphaaromatic compounds such as
phosphabenzene and phosphaferrocene.[11, 12]
moiety through two phosphorus atoms. The aryl rings C and D
on the phosphorus atoms are nearly perpendicular to the main
framework A, whereas the almost parallel arrangement of
phenyl groups E and F and the cyclobutene ring B suggests
Complexes
1 3 were synthesized by treating [{Pd-
(h3-allyl)Cl}2][13] with the corresponding diphosphinidenecy-
À
partial p conjugation between them. The C(53) C(54) and
clobutene ligand and silver trifluoromethanesulfonate
À
C(54) C(55) bond lengths (1.383(8) and 1.376(8) ä) and the
C(53)-C(54)-C(55) angle (119.9(5)8) are in the typical ranges
for h -allyl ligands. The three Pd C distances (2.168(5)
2.178(4) ä) are comparable to those of diphosphane ana-
logues (2.168 2.201 ä).[16]
[*] Prof. Dr. F. Ozawa, Dr. T. Minami, H. Okamoto, S. Ikeda, R. Tanaka
Department of Applied Chemistry
Graduate School of Engineering
3
À
Osaka City University
Sumiyoshi-ku, Osaka 558-8585 (Japan)
Fax : (‡81)6-6605-2978
Complex 1 is extremely reactive towards amines [Eq. (1)].
Treatment of 1 with diethylamine (10 mol equiv) in benzene
E-mail: ozawa@a-chem.eng.osaka-cu.ac.jp
Prof. Dr. M. Yoshifuji
Department of Chemistry
Graduate School of Science
Tohoku University
Aoba, Sendai 980-8578 (Japan)
[**] This work was supported by a Grant-in-Aid for Scientific Research
from the Ministry of Education, Science, Sports and Culture, Japan.
at room temperature led to instant formation of 3-(N,N-
diethylamino)propene in 82% yield. Similarly, the reaction
with aniline afforded a 45% yield of 3-(N-phenylamino)pro-
Supporting information for this article is available on the WWW under
http://www.angewandte.com or from the author.
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