Nickel-catalyzed tandem carbostannylation of alkynes and 1,2-dienes with alkynylstannanes

Article abstract of DOI:10.1002/anie.200353649

Alkynes and 1,2-dienes insert into the carbon-tin bond of alkynylstannanes to afford various stannyldienynes in the presence of a nickel catalyst (see scheme). This is the first example of a transition-metal-catalyzed tandem carbometalation of two different carbon-carbon unsaturated bonds.

Full text of DOI:10.1002/anie.200353649

Communications
À
C C Coupling Reactions
Nickel-Catalyzed Tandem Carbostannylation of
Alkynes and 1,2-Dienes with Alkynylstannanes**
Eiji Shirakawa,* Youko Yamamoto, Yoshiaki Nakao,
Shinichi Oda, Teruhisa Tsuchimoto, and
Tamejiro Hiyama*
Carbometalation of carbon–carbon unsaturated bonds
affords versatile synthetic reagents that have a newly
formed carbon–carbon bond and a carbon–metal bond,
which can be used for further construction of carbon frame-
works.[1] In particular, a series of transition-metal-catalyzed
carbostannylations[2] of alkynes,[3] 1,3-dienes[4] and 1,2-
dienes[5] provides us with various substituted organostan-
nanes, which are converted into a variety of conjugated and
nonconjugated olefinic compounds through carbon–carbon
bond forming reactions such as the Kosugi–Migita–Stille
coupling.[6] The high chemoselectivity and mild reactivity of
organostannanes make the sequence of carbostannylation
and subsequent carbon–carbon bond-forming reactions an
attractive synthetic strategy. Herein, we report an example of
a tandem carbostannylation reaction,[7] namely, sequential
insertion of two different carbon–carbon unsaturated bonds
into a tin–alkynyl carbon bond.[8]
Treatment
of
trimethyl(phenylethynyl)tin
(1a,
0.10 mmol) with 1-octyne (2a, 0.60 mmol) and 1,2-heptadiene
(3, 0.30 mmol) in the presence of [Ni(cod)2] (5.0 mmol) and [2-
(dimethylamino)phenyl]diphenylphosphane (pn, 5.0 mmol;
dibutyl ether, 508C, 24 h) gave rise to tandem alkynylstanny-
lation to give a 98:2 mixture[9] of (3Z,6Z)-3-hexyl-1-phenyl-6-
(trimethylstannyl)undeca-3,6-dien-1-yne (4a) and (3Z,6E)-
[*] Prof. Dr. E. Shirakawa,+ Y. Yamamoto, Dr. T. Tsuchimoto
Graduate School of Materials Science
Japan Advanced Institute of Science and Technology
Asahidai, Tatsunokuchi, Ishikawa 923-1292 (Japan)
E-mail: shirakawa@kuchem.kyoto-u.ac.jp
Y. Nakao, S. Oda, Prof. Dr. T. Hiyama
Department of Material Chemistry
Graduate School of Engineering
Kyoto University
Nishigyo-ku, Kyoto 615-8510 (Japan)
Fax: (+81)75-383-2445
E-mail: thiyama@npc05.kuic.kyoto-u.ac.jp
[+] Present address:
Department of Chemistry
Graduate School of Science
Kyoto University
Sakyo-ku, Kyoto 606-8502 (Japan)
Fax: (+81)75-753-3988
[**] Financial support by Grant-in-Aid for Scientific Research on Priority
Areas (A) “Exploitation of Multi-Element Cyclic Molecules” (to ES
and TH) and COE Research on Elements Science, No. 12CE2005 (to
TH) and on United Approach to New Material Science (to TH) from
the Ministry of Education, Culture, Sports, Science and Technology,
Japan is highly acknowledged.
Supporting information for this article is available on the WWW
under http://www.angewandte.org or from the author.
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DOI: 10.1002/anie.200353649
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Chemie
Table 1: Nickel-catalyzed tandem alkynylstannylation of alkynes and 1,2-heptadiene.[a]
trimethylsilylmethyl or trimethyl-
silyl substituent were prepared
(entries 3 and 4). Enynyl- and
silylethynylstannanes also gave
the corresponding trienynes and
dienynes, respectively (entries 5
and 6). In addition to terminal
alkynes and a monosubstituted
allene, an internal alkyne and a
1,1-disubstituted allene reacted,
albeit with much lower yields
(Scheme 1).
Tandem alkynylstannylation
of bis(trimethylstannyl)acetylene
9 with 2a and 3 gave 1:2:2 adducts
10 predominantly, whereas bis(tri-
butylstannyl) analogue 9’ gave a
mixture of 1:1:1 adducts 11’
[Eq. (2)]. The stereochemical
preferences change depending on
whether conditions A or B are
used, as before. Thus, the size of
trialkylstannyl groups effectively
controls the ratio of 10:11 or
10’:11’.
Entry
1
R1
R2
Cond.[b]
t [h]
Yield [%][c]
4:5[c]
Product(s)
Ph (1a)
Hex (2a)
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
24
24
24
24
24
49
24
24
24
6
56
73
55
33
49
12
49
59
35
5
31
31
44
67
31
61
60
57
98:2
4:96
4a, 5a
4a, 5a
5a
4’a, 5’a
5’a
1:>99
82:18
1:>99
1:>99
96:4
12:88
14:86
>99:1
10:90
7:93
>99:1
6:94
9:91
51:49
5:95
8:92
2[d]
Ph (1’a)
Hex (2a)
5’a
3
Ph (1a)
Me3SiCH2 (2b)
Me3Si (2c)
Hex (2a)
4b, 5b
4b, 5b
4b, 5b
4c
4c, 5c
4c, 5c
4d
4d, 5d
4d, 5d
4e, 5e
4e, 5e
4e, 5e
4
Ph (1a)
8
6
5
CH2 =CMe (1b)
Et3Si (1c)
4.5
6
24
10
9
6
Hex (2a)
Some pieces of evidence are
available to contribute towards a
discussion of the mechanism of the
tandem reaction. An oxidative
adduct of tributyl(phenylethynyl)-
tin (1’a) to a Ni0–pn complex was
observed by 31P NMR and
8
[a] The reaction was carried out in solvent (0.15 mL) with an alkynylstannane (0.10 mmol), an alkyne
(0.60 mmol) and 1,2-heptadiene (0.30 mmol) in the presence of [Ni(cod)2] (5.0 mmol) and a ligand.
[b] Ligand and solvent for Conditions A: pn (5.0 mmol), dibutyl ether; B: ttpp (10 mmol), toluene; C: dpp
(5.0 mmol), THF. [c] Determined by 119Sn NMR spectroscopy with Me4Sn (Bu4Sn for entry 2) as an
internal standard. [d] Tributyl(phenylethynyl)tin was used instead of the trimethylstannyl analogue.
isomer 5a in 56% yield [Eq. (1) and entry 1 of Table 1].[10]
Screening of effective ligands led us to find that tris[p-
(trifluoromethyl)phenyl]phosphane (ttpp) and 2-(diphenyl-
phosphanyl)pyridine (dpp) gave the products in comparable
yields[11] (entry 1 of Table 1) but in preference for 5a over 4a
for conditions B and C (see Figure 1). Worthy of note is that
4a or 5a is generated in each case with selectivities higher than
96% out of 48 possible isomers.
Figure 1. Ligands and solvents used in the tandem alkynylstannylation
for conditions A, B, and C.
The tandem alkynylstannylation conditions A (pn in
dibutyl ether), B (ttpp in toluene) or C (dpp in THF) were
applied to various alkynylstannanes, alkynes and 1,2-hepta-
diene (entries 2–6 of Table 1). Tributylstannyl(phenyl)acety-
lene (1’a) also participated in the reaction (entry 2) but less
efficiently. Similarly, stannyldienynes 4 and 5 that have a
Scheme 1. Tandem alkynylstannylation by using an internal alkyne or a
1,1-disubstituted allene. Reagents and conditions are the same as
those in Table 1.
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A survey of side products in the tandem alkynylstanny-
lation of 1a, 2a, and 3 also provided information on the
reaction order. Formation of any alkyne-alkynylstannylation
product was not observed to any extent under conditions A,
B, or C,[18] whereas a small amount of an allene-alkynylstan-
nylation product was isolated under conditions A and B.[19]
The results clearly show that 1,2-diene 3 rather than alkyne 2a
reacts with 12–pn.
With the above data in hand, cycles 1 and 2 (see Scheme 3)
may rationally explain the formation of tandem alkynylstan-
119Sn NMR spectroscopies (Scheme 2),[12,13] while the reaction
of [Ni(cod)2]–pn with trimethylstannyl analogue 1a gave a
complex mixture. On treatment of 1’a with [Ni(cod)2]
Scheme 3. Plausible catalytic cycles that start with oxidative addition of
an alkynylstannane to a nickel(0) complex.
nylation products 4a and 5a from the reaction of 1a with 2a
and 3. The catalytic cycles start with oxidative addition of 1a
to a nickel(0) complex. When oxidative adduct 12 undergoes
insertion of 3 in a manner similar to acylstannane-nickel(0)
Scheme 2. Oxidative addition of an alkynylstannane to a nickel(0)–pn
complex and the subsequent reactions traced by 31P NMR and
119Sn NMR spectroscopies: [a] Percentage of integral with respect to all
of the observed peaks; [b] Yield based on 1’a (determined by 119Sn
oxidative adducts,[20] 3 should insert into the Ni Sn bond of 12
À
in a direction such to avoid steric repulsion of the Bu
substituent to give an (E)-s-allylnickel complex,[21] which is
prone to isomerize into the more stable anti-p-allyl complex
14. Alkyne 2a should then insert into the bond between the
nickel atom and the nonsubstituted allyl carbon atom of 14 or
the corresponding syn-isomer 15.[22,23] The stereoselectivity of
the tandem alkynylstannylation products should be deter-
NMR spectroscopy with Bu Sn as an internal standard); [c] J and
À
P 119Sn
4
J were not resolved.
P 117Sn
À
(1.0 equiv) and pn (1.0 equiv) in N-methylpyrrolidone
(NMP)[14] in an NMR tube, two sets (12–pn A and 12–pn B)
of distinct signals were observed both in 31P NMR and
À
mined by the relative rate of insertion of 2a into the Ni C
119Sn NMR spectra. Although the observed JPÀ values in
bond of 14 and anti–syn isomerization from 14 to 15,
depending on ligand pn, ttpp or dpp. Reductive elimination
from 16 or 17 should finally afford 4a or 5a, respectively.[24]
In conclusion, we have disclosed the first example of
transition-metal-catalyzed tandem carbostannylation of two
different carbon–carbon unsaturated bonds. Nickel catalysts
assemble alkynylstannanes, alkynes and 1,2-dienes into
alkenylstannanes having a dienyne structure that is otherwise
hard to access by a direct route. Studies on the details of the
mechanism as well as application of the reaction to other
substrates are in progress.
Sn
À
both sets A and B indicate that a Sn Ni s bond is formed cis
to the P atom,[15] thus suggesting structure 12–pn shown in
Scheme 2, we do not understand why two sets of peaks were
observed. Both of these sets did not change on addition of
alkyne 2a (1.0 equiv) but did so smoothly with 1,2-diene 3
(1.2 equiv) to give 13,[16] which lacks Sn P coupling, thus
À
À
showing that the insertion of 3 took place at the Ni Sn bond
of 12–pn.[17] All attempts to obtain 4’a or any other
carbostannylation products by the reaction of 13 with 2a
were unsuccessful.
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Chemie
obtained from independent experiments from those shown in
Table 1, entry 1.
Experimental Section
Tandem alkynylstannylation of alkynes and 1,2-dienes, general
procedure: 1,2-Diene (0.30 mmol) and an alkyne (0.60 mmol) were
added to a solution that contained an alkynylstannane (0.10 mmol),
[Ni(cod)2] (1.4 mg, 5.1 mmol) and a ligand (pn: 1.5 mg, 4.9 mmol; ttpp:
4.7 mg, 10 mmol; dpp: 1.3 mg, 4.9 mmol) in a solvent (dibutyl ether,
toluene, or THF: 0.15 mL), and the resulting mixture was stirred at
508C. After the time specified (see Table 1 and Scheme 1 for specific
details), the mixture was diluted with diethyl ether and filtered
through a pad of florisil. The crude product was analyzed by
119Sn NMR spectroscopy with Me4Sn (Bu4Sn for the reaction of
tributyl(phenylethynyl)tin) as an internal standard.
ꢀ
[12] [(Ph3P)2Ni(C CPh)(SnMe3)] is reportedly obtained, but in an
analytically impure form, see: B. Cetinkaya, M. F. Lappert, J.
McMeeking, D. E. Palmer, J. Chem. Soc. Dalton Trans. 1973,
1202 – 1208.
ꢀ
[13] Density functional study shows that HC CSnH3 can oxidatively
add to [Ni(PH3)2], see: T. Matsubara, K. Hirao, Organometallics
2002, 21, 4482 – 4489.
[14] Oxidative adduct 12–pn was observed also in dibutyl ether, THF,
[D6]benzene or DMF but in a purity less than 50%. NMP as a
solvent for the Ni–pn-catalyzed reaction of 1a with 2a and 3 was
found to be as efficient as dibutyl ether in the yield and
stereoselectivity.
Received: December 30, 2003
Revised: April 21, 2004 [Z53649]
[15] The JPÀ
of oxidative adduct of 1’a to a palladium–imino-
Sn(cis)
phosphane or dppp complex is reported to be 21 or 29 Hz,
respectively, whereas the JPÀSn(trans) of the dppp complex is 1479/
1411 Hz. See, E. Shirakawa, H. Yoshida, T. Hiyama, Tetrahedron
À
Keywords: C C coupling · metalation ·
multicomponent reactions · nickel · tin
.
Lett. 1997, 38, 5177 – 5180. The JP-119
and JP-119
of a
Sn(cis)
Sn(trans)
ꢀ
similar complex, [(dppe)Pd(SnMe2Cl)(C CMe)], prepared by
successive transmetalation of the corresponding dichloro com-
plex, are reported to be 183 and 2392 Hz. See, C. Stader, B.
Wrackmeyer, J. Organomet. Chem. 1985, 295, C11 – C15.
[16] Complex 12-pn reacted with 3 also in the presence of 2a
(1.0 equiv) to give 13.
[1] P. Knochel in Comprehensive Organic Synthesis, Vol. 4 (Eds.:
B. M. Trost, I. Fleming, M. F. Semmelhack), Pergamon, New
York, 1991, chap. 4.4, pp. 865 – 911.
[2] For accounts, see: a) E. Shirakawa, T. Hiyama, Bull. Chem. Soc.
Jpn. 2002, 75, 1435 – 1450; b) E. Shirakawa, T. Hiyama, J.
Organomet. Chem. 2002, 653, 114 – 121.
[3] a) E. Shirakawa, H. Yoshida, T. Kurahashi, Y. Nakao, T. Hiyama,
J. Am. Chem. Soc. 1998, 120, 2975 – 2976; b) E. Shirakawa, K.
Yamasaki, H. Yoshida, T. Hiyama, J. Am. Chem. Soc. 1999, 121,
10221 – 10222; c) E. Shirakawa, H. Yoshida, Y. Nakao, T.
Hiyama, Org. Lett. 2000, 2, 2209 – 2211; d) H. Yoshida, E.
Shirakawa, T. Kurahashi, Y. Nakao, T. Hiyama, Organometallics
2000, 19, 5671 – 5678; e) H. Yoshida, Y. Honda, E. Shirakawa, T.
Hiyama, Chem. Commun. 2001, 1880 – 1881; f) E. Shirakawa, Y.
Yamamoto, Y. Nakao, T. Tsuchimoto, T. Hiyama, Chem.
Commun. 2001, 1926 – 1927.
[4] E. Shirakawa, Y. Nakao, H. Yoshida, T. Hiyama, J. Am. Chem.
Soc. 2000, 122, 9030 – 9031.
[5] a) E. Shirakawa, Y. Nakao, T. Hiyama, Chem. Commun. 2001,
263 – 264; b) E. Shirakawa, Y. Nakao, T. Tsuchimoto, T. Hiyama,
Chem. Commun. 2002, 1962 – 1963.
[6] For an account on the cross-coupling reaction by using
carbostannylation products, see reference [2b]. For a review of
the palladium-catalyzed coupling of organostannanes with
organic electrophiles, see: K. Fugami, M. Kosugi, Top. Curr.
Chem. 2002, 219, 87 – 130, and references therein.
[7] We have already reported the dimerization–carbostannylation
of alkynes, in which two molecules of alkynes insert into a
carbon–tin bond: a) E. Shirakawa, H. Yoshida, Y. Nakao, T.
Hiyama, J. Am. Chem. Soc. 1999, 121, 4290 – 4291; b) H.
Yoshida, E. Shirakawa, Y. Nakao, Y. Honda, T. Hiyama, Bull.
Chem. Soc. Jpn. 2001, 74, 637 – 647.
[17] We could not obtain further information on the structure of
complex 13: its short lifetime and insufficient purity in addition
to low availability of deuterated NMP do not allow us to gain
meaningful 13C and 1H NMR spectra.
[18] The reaction of 1a with 2a in the absence of 3 under conditions
A or B gave (Z)-2-hexyl-4-phenyl-1-trimethylstannylbut-1-en-3-
yne in 13% or 6% yield, respectively. For the nickel-catalyzed
alkynylstannylation of alkynes, see reference [3b].
[19] (Z)-4-Trimethylstannyl-1-phenylnon-4-en-1-yne or 3-butyl-5-
phenyl-2-trimethylstannylpent-1-en-4-yne was generated in 6%
yield under conditions A or B, respectively. For the nickel-
catalyzed alkynylstannylation of 1,2-dienes, see reference [5b].
[20] In the nickel-catalyzed acylstannylation of 1,2-dienes, oxidative
adducts of acylstannanes to nickel(0) complexes are considered
À
to accept insertion of 1,2-dienes at the Ni Sn bonds in the
direction that affords s-allylnickel complexes. See referen-
ce [5a].
[21] Intermediary s-allylnickel complexes, which should be involved
in cycle 1 and 2, are omitted from Scheme 3 for clarity.
[22] The regioselection should be reasonable, as terminal alkynes are
considered to insert into a p-allylnickel complex at a less
substituted carbon in the nickel-catalyzed three-component
coupling of allyl chlorides, alkynes, and alkynylstannanes, see:
a) S. Ikeda, D.-M. Cui, Y. Sato, J. Org. Chem. 1994, 59, 6877 –
6878; b) D.-M. Cui, T. Tsuzuki, K. Miyake, S. Ikeda, Y. Sato,
Tetrahedron 1998, 54, 1063 – 1072.
[23] When allylnickel complexes fail to accept insertion of 2a,
alkynylstannylation products of 3 should be generated through
reductive elimination.
[24] Oxidative cyclization of 2a and 3 with a nickel(0) complex
followed by the reaction with 1a may be an alternative
mechanism, but no evidence is currently available. See refer-
ence [7].
[8] For nickel-catalyzed multicomponent coupling reactions, see:
a) J. Montgomery, Acc. Chem. Res. 2000, 33, 467 – 473; b) S.
Ikeda, Acc. Chem. Res. 2000, 33, 511 – 519.
[9] Configuration of two double bonds in the tandem alkynylstan-
nylation products was determined by NMR spectroscopic studies
on coupling constants (3JSn and JSn C) and NOE. For details,
3
À
H
À
see Supporting Information.
[10] Unless otherwise noted, the yields and the ratio of isomers were
determined by 119Sn NMR spectroscopy with Me4Sn or Bu4Sn as
an internal standard.
[11] The isolated yield of 4a and 5a after purification with reversed
phase chromatography (octadecylsilyl, ODS) followed by gel-
permeation chromatography (GPC) under conditions A or B
(Figure 1) was 50% (88:12) or 63% (2:98), respectively,
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