5964
Y. Masuyama, M. Marukawa / Tetrahedron Letters 48 (2007) 5963–5965
Table 1. Allylation of PhCHO and CH3(CH2)5CHO with 1a
M
M = Pd
R2CHO
Entry
R
Catalyst/mmol
Time (h) 2, Yielda (%)
OR1
SnCl2OR1
M
SnCl2
SnCl2OR1
1
2
3
4
5
6
Ph
Ph
Ph
PdCl2(PhCN)2/0.02 24
[RhCl(cod)]2/0.01
[IrCl(cod)]2/0.01
55
60
84
29
9
1
24
24
A
B
C6H13 PdCl2(PhCN)2/0.02 48
C6H13 [RhCl(cod)]2/0.01
C6H13 [IrCl(cod)]2/0.01
M = Rh or Ir
H3O+
48
48
63
OSnCl2OR1
R2
OH
R2
a Isolated yields based on aldehydes. The structures were confirmed by
the comparison of spectroscopic values (IR and 1H NMR) with those
of authentic samples.4,7
2
C
Scheme 1.
Table 2. Iridium-catalyzed carbonyl allylation with 1
A plausible mechanism is illustrated in Scheme 1. Alk-
oxy groups such as butoxy, 2-hydroxypropoxy, glycidyl-
oxy, and allyloxy would function as leaving groups with
the assistance of tin(II) chloride in the formation of
p-allylmetal complexes A from allyl ethers 1. And then
the p-allylrhodium or -iridium complexes A (M = Rh
or Ir) might directly react with aldehydes to produce
3-buten-1-ols 2, similarly to the rhodium- or iridium-
catalyzed carbonyl allylation by allylic alcohols with
tin(II) chloride,5,6,9,10 and p-allylpalladium complexes
A (M = Pd) might be transformed into allyltin interme-
diates B that would cause nucleophilic attack to alde-
hydes to produce 3-buten-1-ols 2, similarly to the
palladium-catalyzed carbonyl allylations by allylic alco-
hols and esters with tin(II) chloride.2,11 In the case of
diallyl ether (3), a second allyl moiety (R1 = allyl) in C
would be converted to a p-allylmetal complex with the
assistance of another tin(II) chloride to cause second
nucleophilic addition to aldehydes.
Entry
Allylic
ether/mmol
R2
Time (h)
2, Yielda
(%)
1
2
3b
4
5
6
7
8
9
10
11
12
13
14
15
1a/1.2
1a/1.2
1a/1.2
1a/1.2
1a/1.2
1a/1.2
1b/1.2
1b/1.2
1b/1.2
1b/1.2
1b/1.2
1c/1.2
1c/1.2
1d/1.2
1d/1.2
4-ClC6H4
PhCH@CH
PhCH@CH
PhCH2CH2
c-C6H11
PhCH(CH3)
Ph
4-ClC6H4
PhCH@CH
PhCH2CH2
C6H13
24
24
72
24
48
48
46
45
48
48
48
24
24
24
24
71
32
33
63
8
19
85
63
25
60
48
74
57
91
93
Ph
C6H13
Ph
C6H13
a Isolated yields based on aldehydes. The structures were confirmed by
the comparison of spectroscopic values (IR and 1H NMR) with those
of authentic samples.4,7
b The reaction was carried out at 25 °C.
References and notes
Diallyl ether (3) can also be applied to the iridium-cata-
lyzed carbonyl allylations, as summarized in Table 3
(Eq. 3). Both allyl moieties in 3 serve for the carbonyl
allylation (entries 3–7). The allylation of benzaldehyde
1. (a) Trost, B. M.; Verhoeven, T. R. In Comprehensive
Organometallic Chemistry; Pergamon Press: Oxford, 1982;
Vol. 8, p 799; (b) Tsuji, J. In Palladium Reagents and
Catalysts, Innovations in Organic Synthesis; Wiley: New
York, 1995; p 290.
2. (a) Masuyama, Y. J. Synth. Org. Chem. Jpn. 1992, 50, 202;
(b) Masuyama, Y. In Advances in Metal-Organic Chem-
istry; Liebeskind, L. S., Ed.; JAI Press: Greenwich, CT,
1994; Vol. 3, p 255; (c) Tamaru, Y. In Perspectives in
Organopalladium Chemistry for the XXI Century; Tsuji, J.,
Ed.; Elsevier Science: Switzerland, 1999; p 215; (d)
Tamaru, Y. In Handbook of Organopalladium Chemistry
for Organic Synthesis; Negishi, E., Ed.; Wiley: New York,
2002; p 1917.
with
3
also proceeded using PdCl2(PhCN)2 or
[RhCl(cod)]2 as a catalyst to afford 1-phenyl-3-buten-
1-ol (2, R = Ph) in 51% or 53% yield, respectively
(entries 1 and 2). The use of four equimolar amounts
of tin(II) chloride to 3 in the palladium-catalyzed allyl-
ation enhanced the yield (entry 1).
Table 3. Allylation of aldehydes with 3
Entry aldehyde
Catalyst/mmol
Time 2, Yielda
3. For the allylic alkylation with a view to palladium-
catalyzed deallylation of allyl alkyl ethers, see: Tsuka-
moto, H.; Kondo, Y. Synlett 2003, 1061, and references
cited therein.
4. Takahara, J. P.; Masuyama, Y.; Kurusu, Y. J. Am. Chem.
Soc. 1992, 114, 2577.
5. Masuyama, Y.; Kaneko, Y.; Kurusu, Y. Tetrahedron Lett.
2004, 45, 8969.
6. Masuyama, Y.; Chiyo, T.; Kurusu, Y. Synlett 2005, 2251.
7. Ito, A.; Kishida, M.; Kurusu, Y.; Masuyama, Y. J. Org.
Chem. 2000, 65, 494.
(h)
(%)
1
2
3
4
5
6
7
PhCHO
PhCHO
PhCHO
4-ClC6H4CHO
PhCH@CHCHO [IrCl(cod)]2/0.01
Ph(CH2)2CHO
C6H13
PdCl2(PhCN)2/0.02 24
51(76)b
53
[RhCl(cod)]2/0.01
[IrCl(cod)]2/0.01
[IrCl(cod)]2/0.01
24
24
21
46
24
24
69
87
38c
94
[IrCl(cod)]2/0.01
[IrCl(cod)]2/0.01
64
a Isolated yields based on aldehydes. The structures were confirmed by
the comparison of spectroscopic values (IR and 1H NMR) with those
of authentic samples.4,7
b The figure in parentheses is the yield with 2.4 mmol of SnCl2.
c The reaction was carried out at 25 °C.
8. To the solution of 1a (1.2 mmol), benzaldehyde (1.0 mmol)
and tin(II) chloride (1.2 mmol) in THF (1 mL) and H2O
(0.1 mL) was added [IrCl(cod)]2 (0.01 mmol), and then the