Carbonyl allylations by allylic chlorides utilizing a reduction of tin(IV) iodide to triiodostannate(II) species with iodide sources

Article abstract of DOI:10.1016/j.tetlet.2005.02.113

Carbonyl allylations by allylic chlorides either with tin(IV) iodide and tetrabutylammonium iodide (TBAI) in dichloromethane or with tin(IV) iodide and sodium iodide in 1,3-dimethylimidazolidin-2-one at room temperature produced the corresponding homoallylic alcohols. The carbonyl allylations probably proceeded via the reduction of tin(IV) iodide to triiodostannate(II) species with iodide sources such as TBAI and NaI, which led to the construction of a tin(IV)-catalytic cycle based on regeneration of tin(IV) iodide via the transmetalation of homoallyloxytriiodotin to homoallyloxytrimethylsilane with iodotrimethylsilane.

Full text of DOI:10.1016/j.tetlet.2005.02.113

Tetrahedron
Letters
Tetrahedron Letters 46 (2005) 2861–2863
Carbonyl allylations by allylic chlorides utilizing a reduction
of tin(IV) iodide to triiodostannate(II) species with iodide sources
*
Yoshiro Masuyama, Kaori Takeuchi and Yasuhiko Kurusu
Department of Chemistry, Sophia University, 7-1 Kioicho, Chiyoda-ku, Tokyo 102-8554, Japan
Received 29 January 2005; revised 15 February 2005; accepted 21 February 2005
Abstract—Carbonyl allylations by allylic chlorides either with tin(IV) iodide and tetrabutylammonium iodide (TBAI) in dichloro-
methane or with tin(IV) iodide and sodium iodide in 1,3-dimethylimidazolidin-2-one at room temperature produced the correspond-
ing homoallylic alcohols. The carbonyl allylations probably proceeded via the reduction of tin(IV) iodide to triiodostannate(II)
species with iodide sources such as TBAI and NaI, which led to the construction of a tin(IV)-catalytic cycle based on regeneration
of tin(IV) iodide via the transmetalation of homoallyloxytriiodotin to homoallyloxytrimethylsilane with iodotrimethylsilane.
Ó 2005 Elsevier Ltd. All rights reserved.
Allylic trihalotins, derived from starting allylic com-
1
has led to the construction of a tin(IV) iodide-catalytic
cycle with iodotrimethylsilane in DMI.
2
2,3
pounds, such as allylic halides, alcohols, and esters
with tin(II) halides, are one of the most convenient all-
SnI 1.5 mmol
TBAI 3.0 mmol
4
,5
4
ylating agents in Barbier-type carbonyl allylations.
OH
These need a stoichiometric amount of metals or metal
compounds as reducing agents like tin(II) halides to
form allylic trihalotins. No Barbier-type carbonyl allyl-
ation with a catalytic amount of a metal reducing agent
and a stoichiometric amount of non-metal reducing
agents has been known. We have found that a combo-
reagent of tin(IV) chloride and tetrabutylammonium io-
dide (TBAI) functions as a reducing agent similar to
tin(II) halides for the Barbier-type carbonyl allylations
Cl
+
RCHO
CH Cl 3 ml
R
2
2
r. t.
1, 1.5 mmol
1.0 mmol
2
ð1Þ
We first found that tin(IV) iodide functioned similar to
tin(IV) chloride for Barbier-type carbonyl allylation
with a combo-reagent of tin(IV) chloride and TBAI
6
with allylic halides. Tin(IV) chloride is probably re-
(Eq. 1, Table 1). The balance between the yield and
duced to trichlorostannate(II) by TBAI via the forma-
tion of iodotetrachlorostannate(IV). This reduction
of tin(IV) to stannate(II) with TBAI led us to plan
a tin(IV)-catalytic cycle for Barbier-type carbonyl
allylation based on regeneration of tin(IV) halide by
transmetalation of homoallyloxytrihalotin with halotri-
the reaction rate determined optimal conditions; the
allylation of benzaldehyde (1.0 mmol) by 3-chloropro-
pene (1, 1.5 mmol) was carried out with tin(IV) iodide
(
(
1.5 mmol) and TBAI (3.0 mmol) in dichloromethane
3 mL) at room temperature (Eq. 1, R = C H ; entry 3
6
5
in Table 1). The amount of TBAI was cut down by
6
the use of tin(IV) iodide instead of tin(IV) chloride.
7
methylsilane. However, no tin(IV) chloride-catalytic
cycle with TBAI and chlorotrimethylsilane in dichloro-
methane could be constructed. We here report that
changing tin(IV) chloride into tin(IV) iodide not only
has smoothly caused the Barbier-type carbonyl allyla-
tion by allylic chlorides with TBAI or NaI, but also
Dichloromethane is superior to other solvents such as
THF and DMF. The allylation of various aldehydes
with 1 was carried out under the same conditions as
the optimal conditions of benzaldehyde (Method A).
Some representative results are summarized in Table 2
(
(
entries 1–9). Using 1,3-dimethylimidazolidin-2-one
DMI, 2 mL) as a solvent, which could not be used in
Keywords: Nucleophilic addition; Carbonyl allylation; Tin(IV)-cata-
lytic cycle; Allylic tins; Tin(IV) iodide.
the case of tin(IV) chloride, we applied sodium iodide in-
stead of TBAI to the carbonyl allylation by 1 with
tin(IV) iodide (Method B, entries 10–18 in Table 2).
*
Corresponding author. Tel.: +81 3 3238 3453; fax: +81 3 3238
361; e-mail: y-masuya@sophia.ac.jp
3
0
040-4039/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2005.02.113

2862
Y. Masuyama et al. / Tetrahedron Letters 46 (2005) 2861–2863
Table 1. Allylation of PhCHO by 1 with SnI
4
and TBAI for 40 h
by method B (Eq. 2, Table 3). The reaction led to syn-
8
a
selection accompanied by c-regioselection. The c-syn
Entry
TBAI/mmol
Solvent
6 5
2 (R = C H ), Yield/%
selection can be explained by the non-Lewis acidity of
the tin in 2-butenylpolyiodotin intermediate that forms
unusual Lewis acid-non-participating acyclic antiperi-
planar transition states with aldehydes, similar to the
carbonyl allylation with tin(II) iodide, TBAI and NaI
1
2
3
4
1.5
2.0
3.0
4.0
3.0
3.0
3.0
8
CH
CH
CH
CH
CH
2
2
2
2
2
Cl
Cl
Cl
Cl
Cl
2
2
2
2
2
15
35
68
63
12
53
30
b
5
1
0,11
6
7
THF
DMF
(Scheme 1).
OH
OH
a
Isolated yields.
Cl + RCHO
+
b
The reaction was carried out at 0 °C.
R
R
3
4s
4a
Table 2. Carbonyl allylations by 1 with TBAI or NaI
ð2Þ
a
Entry
R
Method
Time/h
2, Yield/%
1
2
3
4
5
6
7
8
9
C
6
H
5
A
A
A
A
A
A
A
A
A
B
B
B
B
B
B
B
B
B
24
23
26
24
25
24
45
48
24
24
24
24
24
26
23
50
52
45
68
92
84
58
58
64
69
50
The tin(IV)-catalytic cycle was constructed by using
tin(IV) iodide (0.05 mmol), TBAI (0.10 mmol), sodium
iodide (3.0 mmol), iodotrimethylsilane (1.1 mmol), 1
(1.5 mmol), and benzaldehyde (1.0 mmol) in DMI
4-ClC
4-MeOOCC
2-MeOC H
4
6 4
H
6
H
4
6
C
C
C
6
H
6
H
6
H
5
CH@CH
CH CH
5
2
2
(1 mL) at room temperature (48 h, 2 (R = C H ),
6 5
13
5
8%). Even if TBAI (3.0 mmol) was used instead of
c-C
6
H
11
TBAI (0.10 mmol) and sodium iodide (3.0 mmol), no
tin(IV)-catalyzed allylation of benzaldehyde occurred
in dichloromethane (2 mL). The allylation of benzalde-
hyde, either with chlorotrimethylsilane instead of iodo-
trimethylsilane or without iodotrimethylsilane, for 48 h
proceeded just stoichiometrically to tin(IV) iodide; using
0.10 mmol of tin(IV) iodide afforded 2 (R = C H ) in
b
C
C
6
H
H
5
(CH
3
)CH
75
10
11
12
13
14
15
16
17
18
6
5
90
99
96
70
71
74
73
73
4-ClC
6 4
H
4-MeOOCC
6
H
4
4-NCC
6
H
4
4-MeOC
6
H
4
C
C
6
H
H
5
CH=CH
6
5
6
13
about 10% yield. In the case of no TBAI, the yield of
the allylation of benzaldehyde for 48 h lowered (35%).
Tin(II) iodide functioned as a catalyst similar to tin(IV)
iodide in the allylation of benzaldehyde (35%). Some
aldehydes can be used in the tin(IV)-catalyzed allylation;
4-ClC H CHO (30 h, 70%), C H CH@CHCHO (70 h,
c-C
6
H
11
b
C
6
H
5
(CH
3
)CH
82
a
8
Isolated yields.
2(anti)-Phenyl-5-hexen-3-ol was preferentially produced (entry 9,
syn:anti = 27:73; entry 18, syn:anti = 28:72). The ratios were deter-
1
mined by H NMR analysis (JEOL JNM-LA500).
b
6
4
6
5
8
3
8%), C H CH CH CHO (66 h, 41%), C H CHO
6 5 2 2 6 13
(75 h, 34%). A plausible mechanism for the tin(IV)-cat-
alyzed carbonyl allylation is illustrated in Scheme 2.
Tin(IV) iodide is first reduced to triiodostannate(II)
ion A with iodide sources via the reductive elimination
of iodine from pentaiodostannate(IV) ion. Iodine is
scavenged by another iodide to produce sodium tri-
Aromatic aldehydes bearing an electron-withdrawing
groupor an electron-donating grou p, a,b-unsaturated
aldehyde, and aliphatic aldehydes can be employed in
both methods. No allylation with sodium iodide pro-
ceeded in either dichloromethane or THF. Method A
in dichloromethane is superior to method B in DMI
with respect to workup, while method B has the advan-
tages of yield and cost of iodide sources over method A.
6
,12
iodide.
The stannate(II) ion A causes nucleophilic
substitution to 1 to prepare 2-propenyltriiodotin (B),
which undergoes nucleophilic addition to aldehydes to
afford homoallyloxytriiodotin C. The homoallyloxytri-
iodotin C transmetalates with iodotrimethylsilane to
produce homoallyloxytrimethylsilane D, and then
tin(IV) iodide is regenerated for the sake of tin(IV)-
Regio- and diastereoselectivity were investigated in the
9
reaction of 1-chloro-2-butene (3) and some aldehydes
7
catalytic cycle. Tin(II) iodide may react with iodide
sources to prepare A, which starts the same tin(IV)-
catalytic cycle as that of tin(IV) iodide.
Table 3. Regioselective carbonyl allylations with 3 by means of
method B
a
b
Entry
R
Time/h
4, Yield/%
4s:4a
1
2
3
4
5
6
7
C
4-ClC
6
H
5
46
28
46
70
45
70
70
68
76
40
45
55
63
47
88:12
90:10
87:13
85:15
89:11
81:19
63:37
6
H
4
6
InSn
4-MeOC
H
4
OH
C
C
C
6
6
6
H
H
H
5
CH@CH
CH CH
H
R
H
5
2
2
R
13
H C
3
c-C
6
H
11
O
a
8
4s
Isolated yields.
The ratios were determined by H NMR analysis (JEOL JNM-
acyclic antiperiplanar
b
1
8
LA500).
Scheme 1. syn-Selection via acyclic antiperiplanar transition state.

Y. Masuyama et al. / Tetrahedron Letters 46 (2005) 2861–2863
2863
NaI
NaI3
I2
I- (NaI or TBAI)
IV
+
II -
Sn I
M Sn I
4
OSiMe3
R
3
Cl
A, M=Na or TBA
1
D
MCl
Me SiI
+
3
H O
3
OSnIVI3
IV
Sn I
3
OH
R
B
C
R
2
RCHO
Scheme 2. A plausible mechanism for the tin(IV)-catalyzed carbonyl allylation.
In conclusion, we have established a Barbier-type car-
bonyl allylation by allylic chloride with triiodostan-
nate(II) species derived from SnI4 and I source
2. (a) Masuyama, Y. J. Synth. Org. Chem., Jpn. 1992, 50,
02; (b) Masuyama, Y. In Advances in Metal-Organic
2
ꢀ
Chemistry; Liebeskind, L. S., Ed.; JAI Press: Greenwich,
CT, 1994; Vol. 3, p255; (c) Masuyama, Y.; Ito, T.; Tachi,
K.; Ito, A.; Kurusu, Y. Chem. Commun. 1999, 1261.
. Matsubara, S.; Wakamatsu, K.; Morizawa, Y.; Tsu-
boniwa, N.; Oshima, K.; Nozaki, H. Bull. Chem. Soc.
Jpn. 1985, 58, 1196.
(
can be reduced with I to triiodostannate(II) species
TBAI or NaI). Noteworthy features are that (1) SnI4
ꢀ
3
without reducing aldehydes, (2) SnI can be regenerated
4
by transmetalation of homoallyloxytriiodotin with iodo-
trimethylsilane; a construction of SnI -catalytic cycle,
4
4. For a review on carbonyl allylations with allylic metals,
see: Yamamoto, Y.; Asao, N. Chem. Rev. 1993, 93, 2207.
5. For reviews on carbonyl allylations with allylic tin
compounds, see: (a) Tagliavini, G. Rev. Si Ge Sn Pb
(
to SnI , and (4) SnI system is superior to SnCl system
from the viewpoints of resource saving of I (TBAI or
NaI) and tractability of tin(IV) halides.
3) SnI can be also used as a starting tin catalyst similar
2
6
4
4
4
ꢀ
1
2
985, 8, 237; (b) Yamamoto, Y. Acc. Chem. Res. 1987, 20,
43; (c) Marshall, J. A. Chem. Rev. 1996, 96, 31.
6
7
. Masuyama, Y.; Suga, T.; Watabe, A.; Kurusu, Y. Tetra-
hedron Lett. 2003, 44, 2845.
Acknowledgement
. For catalytic cycles utilizing transmetalation of metal
homoallyloxide to trimethylsilyl one in carbonyl allyl-
ations with Mn reducing metal catalysts, see: (Cr) F u¨ rst-
ner, A.; Shi, N. J. Am. Chem. Soc. 1996, 118, 2533; (In,
Ge) Auge, J.; Lubin-Germain, N.; Marque, S.; Seg-
hrouchni, L. J. Organomet. Chem. 2003, 679, 79.
This work was supported by a Grant-in-Aid for Scien-
tific Research (C) from Japan Society for the Promotion
of Science (JSPS).
8
. (a) The structures and/or ratios were confirmed by the
comparison of spectroscopic values (IR and H NMR)
1
References and notes
with those of authentic samples. See: Takahara, J. P.;
Masuyama, Y.; Kurusu, Y. J. Am. Chem. Soc. 1992, 114,
2577; (b) Ref. 1i.
1
. (a) Mukaiyama, T.; Harada, T.; Shoda, S. Chem. Lett.
980, 1507; (b) Gambaro, A.; Peruzzo, V.; Plazzogna, G.;
1
Tagliavini, G. J. Organomet. Chem. 1980, 197, 45; (c)
Auge, J.; David, S. Tetrahedron Lett. 1983, 24, 4009; (d)
Uneyama, K.; Kamaki, N.; Moriya, A.; Torii, S. J. Org.
Chem. 1985, 50, 5396; (e) Molander, G. A.; Shubert, D. C.
J. Am. Chem. Soc. 1986, 108, 4683; (f) Imai, T.; Nishida, S.
J. Chem. Soc., Chem. Commun. 1994, 277; (g) Kundu, A.;
Prabhakar, S.; Vairamani, M.; Roy, S. Organometallics
9. The E:Z ratio of 1-chloro-2-butene, purchased from
Aldrich Chemical Co., Inc., is 95:5 (500 MHz H NMR).
10. For a review on regio- and diastereocontrol in carbonyl
allylation with tin(II) halides, see: Masuyama, Y. Recent
Res. Dev. Org. Chem. 2000, 4, 373.
11. For Lewis base-promoted carbonyl allylation, see: Den-
mark, S. E.; Fu, J. J. Am. Chem. Soc. 2001, 123, 9488, and
references cited therein.
1
1
997, 16, 4796; (h) Masuyama, Y.; Ito, A.; Kurusu, Y.
Chem. Commun. 1998, 315; (i) Ito, A.; Kishida, M.;
Kurusu, Y.; Masuyama, Y. J. Org. Chem. 2000, 65, 494.
12. Tsuritani, T.; Ito, S.; Shinokubo, H.; Oshima, K. J. Org.
Chem. 2000, 65, 5066.