A new synthesis of aldehydes by the palladium-catalyzed reaction of 2-pyridinyl esters with hydrosilanes

Article abstract of DOI:10.1055/s-2006-939058

A new synthesis of aldehydes by the palladium-catalyzed reaction of 2-pyridinyl esters with hydrosilanes is described. The reaction is applicable to the preparation of aliphatic, aromatic, and α,β-unsaturated aldehydes. Various functional groups, such as fluoro, methoxy, aldehyde, acetal, and ester, are tolerated. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-2006-939058

LETTER
869
A New Synthesis of Aldehydes by the Palladium-Catalyzed Reaction of
2-Pyridinyl Esters with Hydrosilanes
P
alladium
u
-Catalyze
d
S
n
ynthesis of
A
ldehy
N
des akanishi, Hiroto Tatamidani, Yoshiya Fukumoto, Naoto Chatani*
Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
Fax +81(6)68797396; E-mail: chatani@chem.eng.osaka-u.ac.jp
Received 28 January 2006
an improvement in the Fukuyama reaction to make it
more practical, from the viewpoint of an industrial pro-
cess.6 Yamamoto reported that in situ mixed acid anhy-
drides, generated from carboxylic acids and pivalic
anhydride, can be used in the synthesis of aldehydes in
Pd-catalyzed hydrogenation reactions.7 Gooßen subse-
quently reported that sodium hypophosphite, NaH2PO2, is
more practical as a reducing reagent in the hydrogenation
of acid anhydrides.8 We recently discovered that 2-pyri-
dinyl esters serve as good substrates, compared to acid
chlorides for Pd-catalyzed cross-coupling reactions with
arylboronic acids.9 We also reported that yne-2-pyridinyl
esters are more reactive than yne-acid chlorides in Pd-cat-
alyzed cyclocarbonylation reactions.10 Herein, we wish to
report on an efficient method for the preparation of alde-
hydes by the palladium-catalyzed reaction of 2-pyridinyl
esters with hydrosilanes.
Abstract: A new synthesis of aldehydes by the palladium-cata-
lyzed reaction of 2-pyridinyl esters with hydrosilanes is described.
The reaction is applicable to the preparation of aliphatic, aromatic,
and a,b-unsaturated aldehydes. Various functional groups, such as
fluoro, methoxy, aldehyde, acetal, and ester, are tolerated.
Key words: catalysis, 2-pyridinyl esters, hydrosilanes, aldehydes,
palladium
The hydrogenation of carboxylic acid chlorides catalyzed
by palladium complexes is referred to as the Rosenmund
reduction.1 The reaction is useful for the preparation of al-
dehydes and is frequently utilized for the synthesis of use-
ful compounds and natural products.2 A number of
attempts to improve the Rosenmund reduction have been
made over the years.2 Improvements in Pd-catalyzed reac-
tions of acid chlorides have utilized alternative hydrogen
3
4
sources. The use of HSiEt3 or HSnBu3 in place of H2 is
also effective for reducing acid chlorides to aldehydes.
Modifications of substrates using alternate leaving groups
in place of chloride have also been carried out because
acid chlorides are not easily handled compounds and are
susceptible to racemization because of the acidity of the
C–H bond a to the carbonyl group. Fukuyama reported an
elegant synthesis of aldehydes through the reduction of
thioesters with HSiEt3 in the presence of Pd/C, and
showed that no racemization occurs, even in reactions of
optically active amino acid derivatives.5 Seki reported on
Treatment of 2-pyridinol-2-naphthoate (1, 1 mmol) with
triethylsilane (TES) (2 mmol) in the presence of Pd(OAc)2
(0.03 mmol) and PPh3 (0.09 mmol) in DMF (2 mL) at
60 °C for 12 hours led to the complete consumption of 1,
to give naphthalene-2-carbaldehyde (2) in 91% isolated
yield (>99% GC yield) (Equation 1). No naphthalene,
which is formed by decarbonylation of the aldehyde 2,
was detected. The use of other solvents resulted in de-
creased yields (toluene 51%, THF 47%, dioxane 42%,
MeCN 35%, 1,2-dichloroethane 26%). The use of dimeth-
ylphenylsilane also gave 2 in a comparable yield (82%
O
H
O
Pd(OAc)2
PPh3
0.03 mmol
0.09 mmol
+
O
N
HSiEt3
DMF
2 mL
60 °C, 12 h
2 91%
1 1 mmol
2 mmol
Equation 1
O
OSiEt3
Pd(OAc)2
0.03 mmol
2 mL
+
O
N
HSiEt3
DMF
60 °C, 12 h
1 1 mmol
2 mmol
3 48%
Equation 2
SYNLETT 2006, No. 6, pp 0869–0872
0
4.
0
4.
2
0
0
6
Advanced online publication: 14.03.2006
DOI: 10.1055/s-2006-939058; Art ID: U01206ST
© Georg Thieme Verlag Stuttgart · New York

870
J. Nakanishi et al.
LETTER
yield), but other hydrosilanes, such as poly(methylhy- was converted to an aldehyde and the methyl ester group
drosiloxane) (37%), triphenylsilane (28%), triethoxysil- remained intact (entry 3). This also clearly indicates that
ane (24%) were not suitable. The presence of PPh3 (9 the presence of a 2-pyridinyl group is essential for the suc-
mol%) is crucial for the production of aldehydes. The use cess of the reaction. The use of DSiMe2Ph resulted in the
of 6 mol% of PPh3 decreased the product yield to 77% incorporation of deuterium into the product 25 (entry 9).
yield and 1 was recovered in 13% yield. When the reac- The a,b-unsaturated ester 28 can also be reduced to the
tion was carried out in the absence of PPh3, overreduction a,b-unsaturated aldehyde 29 in good yield (entry 11).
took place to give triethyl(naphthalene-2-ylmethyl)silyl
ether (3) in 48% yield, along with traces of the aldehyde 2
(Equation 2).
In summary, a new and efficient method for the synthesis
of aldehydes, involving the palladium-catalyzed coupling
of 2-pyridinyl esters with hydrosilanes, was developed.
Control experiments were carried out in order to better un- The reaction is compatible with various functional groups.
derstand the role of the 2-pyridinyl group. We compared In contrast to the reaction of acid chlorides, in which HCl
the reactivity of 2-pyridinyl ester 1 with 4-pyridinyl ester is liberated, the present reaction proceeds without the
4 and benzyl ester 5 (Figure 1). As a result, 4 and 5 were need for an added base because the neutral 2-triethyl-
unreactive. The effect of a substituent on the pyridine ring siloxypyridine leaving group is neutral.
was next examined. The presence of a methyl group at the
6-position, as in 6, had no effect on the efficiency of the
Table 1 Reaction of 2-Pyridinyl Esters with TES Catalyzed by
Palladium Complexa
Entry 2-Pyridinyl esters
O
reaction, but the presence of a methoxy group at the 4-po-
sition, as in 7, led to low conversion. In contrast to the pre-
viously reported Pd-catalyzed cross-coupling reaction of
2-pyridinyl esters with PhB(OH)2,9 the importance of the
coordination of the pyridine nitrogen to Pd was not ob-
served in the case of 6, probably because of higher reac-
tion temperatures required in the present reaction.
Thioester 8 and acid chloride 9 were not suitable sub-
strates under the reaction conditions used here.
Aldehydeb
Yield (%)
88
O
OPy
H
1
10
11
O
O
O
O
OPy
O
H
O
N
2
3
83
71
O
O
O
O
O
N
12
13
O
1
5
91%
4
6
trace
O
OPy
H
MeO
MeO
O
O
O
O
N
O
14
15
O
O
OPy
H
trace
81%
O
4
76
H
H
OMe
N
O
O
O
16
17
O
O
S
N
O
OPy
H
5
6
7
86
60c
76
MeO
MeO
F
7
9
62%
8
25%
F
O
18
19
O
O
Cl
OPy
H
OMe
OMe
58%
20
21
Figure 1 Comparison between esters endowed with different coor-
dination characteristics
O
O
OPy
Me
H
Me
Both aromatic and aliphatic esters underwent reduction
with HSiEt3 to give the corresponding aldehydes in good
to high yields, as listed in Table 1. Various functional
groups can be tolerated under the reaction conditions em-
ployed. It should be noted that only the 2-pyridinyl ester
OAc
OAc
22
23
Synlett 2006, No. 6, 869–872 © Thieme Stuttgart · New York

LETTER
Palladium-Catalyzed Synthesis of Aldehydes
871
Table 1 Reaction of 2-Pyridinyl Esters with TES Catalyzed by
(15), 51 (28). Anal. Calcd (%) for C10H10O3 (134.13): C, 67.41; H,
5.66. Found: C, 67.12; H, 5.77.
Palladium Complexa (continued)
Entry 2-Pyridinyl esters
Aldehydeb
Yield (%)
55
2-Naphthalenecarboxylic Acid 4-Methoxy-2-pyridinyl Ester (7)
White solid; mp 84 °C. Rf = 0.46 (hexane–EtOAc, 1:1). IR (KBr):
O
O
nmax = 2970, 2939, 1722, 1601, 1566, 1489, 1437, 1406, 1356,
1321, 1265, 1221, 1190, 1153, 1126, 1090, 1030, 993, 957, 891,
852, 822, 756, 563, 476 cm–1. 1H NMR (270 MHz, CDCl3): d = 3.90
(s, 3 H), 6.78–6.84 (m, 2 H), 7.54–7.66 (m, 2 H), 7.90–8.01 (m, 3
H), 8.20 (dd, J = 8.6, 1.3 Hz, 1 H), 8.28 (d, J = 5.9 Hz, 1 H), 8.83 (s,
1 H). 13C NMR (68 MHz, CDCl3): d = 55.62, 101.75, 109.56,
125.45, 126.25, 126.83, 127.80, 128.39, 128.72, 129.53, 132.28,
132.42, 135.91, 149.03, 159.85, 164.84, 168.46. MS: m/z (%) = 279
(6) [M+], 250 (17), 156 (12), 155 (100) [M+ – PyO], 127 (93), 77
(11). Anal. Calcd (%) for C17H13NO3 (279.29): C, 73.11; H, 4.69;
N, 5.02. Found: C, 73.07; H, 4.66; N, 4.99.
OPy
H
8
PyO
H
O
O
24
17
O
O
9
10
11
12
85d
85
74
71
OPy
D
1
25
O
O
1,1¢-Biphenyl-4-carboxylic Acid 2-Pyridinyl Ester (10)
H
OPy
White solid; mp 153 °C. Rf = 0.11 (hexane–EtOAc, 4:1). 1H NMR
(270 MHz, CDCl3): d = 7.23–7.31 (m, 2 H), 7.39–7.52 (m, 3 H),
7.66 (d, J = 7.3 Hz, 2 H), 7.74 (d, J = 8.2 Hz, 2 H), 7.86 (dt, J = 7.9,
26
27
O
O
2.0 Hz, 1 H), 8.30 (d, J = 8.6 Hz, 2 H), 8.48 (d, J = 3.3 Hz, 1 H). 13
C
O
O
NMR (68 MHz, CDCl3): d = 116.67, 122.11, 127.23, 127.33,
127.73, 128.34, 128.97, 130.91, 139.55, 139.77, 146.57, 148.70,
158.22, 164.70. IR (KBr): nmax = 1739, 1606, 1564, 1487, 1462,
1433, 1406, 1267, 1207, 1188, 1176, 1093, 1066, 1007, 995, 918,
891, 858, 773, 746, 696, 594, 519 cm–1. MS: m/z (%) = 275 (3)
[M+], 182 (15), 181 (100) [M+ – PyO], 153 (22), 152 (45), 151 (12).
Anal. Calcd (%) for C18H13NO2 (275.30): C, 78.53; H, 4.76; N,
5.09. Found: C, 78.43; H, 4.82; N, 5.09.
H
H
OPy
OPy
MeO
MeO
29
28
MeO
31
MeO
30
1,3-Benzodioxole-5-carboxylic Acid 2-Pyridinyl Ester (12)
White solid; mp 88 °C. Rf = 0.10 (hexane–EtOAc, 4:1). IR (KBr):
O
H
O
OPy
n
max = 3016, 1730, 1626, 1591, 1493, 1471, 1435, 1365, 1282,
13
41
1269, 1203, 1155, 1097, 1063, 1039, 995, 933, 876, 845, 820, 764,
746, 715, 578, 517 cm–1. 1H NMR (270 MHz, CDCl3): d = 6.09 (d,
J = 2.0 Hz, 2 H), 6.91 (d, J = 8.2 Hz, 1 H), 7.20 (d, J = 8.2 Hz, 1 H),
7.25–7.29 (m, 1 H), 7.64 (d, J = 1.7 Hz, 1 H), 7.81–7.88 (m, 2 H),
8.46 (d, J = 3.0 Hz, 1 H). 13C NMR (68 MHz, CDCl3): d = 101.98,
108.14, 110.01, 116.63, 122.01, 122.86, 126.54, 139.48, 147.89,
148.60, 152.42, 158.20, 164.10. MS: m/z (%) = 243 (5) [M+], 149
(100) [M+ – PyO], 121 (20), 65 (24), 63 (19). Anal. Calcd for
C13H9NO4 (243.21): C, 64.20; H, 3.73; N, 5.76. Found: C, 64.37; H,
3.76; N, 5.77.
32
33
a Reaction conditions: 2-pyridinyl ester (1 mmol), TES (2 mmol),
Pd(OAc)2 (0.03 mmol), PPh3 (0.09 mmol), DMF (2 mL), 60 °C, 12 h.
b Isolated yields.
c For 20 h.
d DSiMe2Ph was used in place of TES.
General Procedure for the Synthesis of Aldehydes
A 10-mL two-necked flask equipped with a reflux condenser con-
nected to a N2 line was flame-dried under a flow N2 and then cooled
to r.t. To the flask were added ester (1 mmol), Pd(OAc)2 (0.03
mmol) and PPh3 (0.09 mmol), and then DMF (2 mL) and silane
(2 mmol) were then added via a syringe. The flask was heated in an
oil bath at 60 °C for 12 h and then cooled. The volatile components
were removed in vacuo and the residue was subjected to column
chromatography on silica gel to give the aldehyde.
4-Formylbenzoic Acid 2-Pyridinyl Ester (16)
White solid; mp 99 °C. Rf = 0.34 (hexane–EtOAc, 1:1). IR (KBr):
nmax = 2858, 1741, 1705, 1593, 1574, 1469, 1427, 1387, 1273,
1203, 1171, 1146, 1078, 1012, 993, 835, 762, 683, 623, 515 cm–1.
1H NMR (270 MHz, CDCl3): d = 7.23–7.34 (m, 2 H), 7.89 (dd,
J = 7.9, 7.7 Hz, 1 H), 8.03 (d, J = 7.9 Hz, 1 H), 8.40 (d, J = 7.9 Hz,
1 H), 8.50 (s, 1 H), 10.15 (s, 1 H). 13C NMR (150 MHz, CDCl3):
d = 116.45, 122.44, 129.62, 130.93, 134.04, 139.73, 139.75,
148.74, 157.88, 163.79, 191.45. MS: m/z (%) = 227 (1) [M+], 199
(26), 133 (100) [M+ – PyO], 105 (28), 77 (26), 51 (29), 50 (13).
Anal. Calcd for C13H9NO3 (227.22): C, 68.72; H, 3.99; N, 6.16.
Found: C 68.59; H, 3.90; N, 6.15.
2-Pyridinyl esters can be easily prepared by the treatment of the cor-
responding acid chlorides with 2-hydroxypyridine in the presence
of K2CO3 in CH2Cl2 at r.t.
3-Acetoxy-2-methylbenzaldehyde (17)
White solid; mp 135 °C. Rf = 0.26 (hexane–EtOAc 4:1). IR (KBr):
3-Fluoro-4-methoxybenzoic Acid 2-Pyridinyl Ester (18)
White solid; mp 66 °C. Rf = 0.31 (hexane–EtOAc, 1:1). IR (KBr):
nmax = 2935, 2819, 1765, 1687, 1604, 1581, 1462, 1410, 1369,
n
max = 3064, 1738, 1728, 1618, 1593, 1522, 1475, 1431, 1333,
1311, 1279, 1209, 1174, 1084, 1039, 928, 866, 827, 766, 752, 710,
675, 609, 565, 519 cm–1. 1H NMR (270 MHz, CDCl3): d = 2.37 (s,
3 H), 2.49 (s, 3 H), 7.27 (d, J = 7.6 Hz, 1 H), 7.39 (t, J = 7.9 Hz, 1
H), 7.72 (d, J = 7.6 Hz, 1 H), 10.27 (s, 1 H). 13C NMR (68 MHz,
CDCl3): d = 11.48, 20.71, 126.78, 127.58, 129.98, 132.64, 135.55,
149.92, 169.07, 191.98. MS: m/z (%) = 178 (15) [M+], 136 (100),
135 (76), 108 (12), 107 (39), 79 (14), 78 (10), 77 (37), 53 (11), 52
1286, 1238, 1194, 1176, 1130, 1099, 1076, 1011, 937, 849, 813,
760, 714, 646, 619, 557, 509 cm–1. H NMR (270 MHz, CDCl3):
1
d = 3.99 (s, 3 H) 7.05 (dd, J = 8.6, 8.4 Hz, 1 H), 7.20 (d, J = 8.2 Hz,
1 H), 7.26–7.31 (m, 1 H), 7.85 (ddd, J = 7.9, 7.8, 6.0 Hz, 1 H), 7.93
(dd, J = 11.5, 2.3 Hz, 1 H), 8.02 (ddd, J = 8.6, 2.0, 1.3 Hz, 1 H), 8.46
(dd, J = 4.8, 1.8 Hz, 1 H). 13C NMR (68 MHz, CDCl3): d = 56.29,
Synlett 2006, No. 6, 869–872 © Thieme Stuttgart · New York

872
J. Nakanishi et al.
LETTER
112.4 (d, J = 2.2 Hz), 116.6, 117.9 (d, J = 20.2 Hz), 121.6 (d,
J = 6.7 Hz), 122.1, 127.7 (d, J = 3.4 Hz), 139.6, 148.7, 151.7 (d,
J = 247.5 Hz), 152.5 (d, J = 10.6 Hz), 158.1, 163.6 (d, J = 2.8 Hz).
MS: m/z (%) = 247 (2) [M+], 153 (100) [M+ – PyO], 125 (12), 110
(10), 95 (14), 82 (11). HRMS: m/z calcd for C13H10FNO3 [M+]:
247.0645; found: 247.0653.
6.51 (d, J = 15.8 Hz, 1 H), 6.94 (d, J = 8.6 Hz, 1 H), 7.17–7.26 (m,
2 H), 7.54 (d, J = 8.9 Hz, 2 H), 7.80 (dd, J = 7.6, 1.6 Hz, 1 H), 7.88
(d, J = 16.1 Hz, 1 H), 8.43 (d, J = 3.3 Hz, 1 H). 13C NMR (68 MHz,
CDCl3): d = 55.39, 114.17, 114.42, 116.56, 121.84, 126.76, 130.13,
139.36, 147.01, 148.55, 158.11, 161.83, 165.12. MS: m/z (%) = 255
(5) [M+], 162 (10), 161 (100) [M+ – PyO], 133 (20). Anal. Calcd for
C15H13NO3 (255.27): C, 70.58; H, 5.13; N, 5.49. Found: C, 70.58;
H, 4.84; N, 5.39.
2-Methoxybenzoic Acid 2-Pyridinyl Ester (20)
Colorless oil. Rf = 0.43 (hexane–EtOAc, 1:1). IR (KBr): nmax
=
3010, 2943, 2841, 1749, 1599, 1491, 1468, 1433, 1230, 1259, 1200,
1167, 1136, 1097, 1078, 1030, 995, 889, 866, 796, 758, 700, 669,
609, 517, 417 cm–1. 1H NMR (270 MHz, CDCl3): d = 3.95 (s, 3 H),
7.02–7.08 (m, 2 H), 7.22–7.27 (m, 2 H), 7.56 (ddd, J = 8.1, 7.5, 1.7
Hz, 1 H), 7.83 (ddd, J = 7.9, 7.7, 1.7, 1 H), 8.11 (dd, J = 7.9, 1.7 Hz,
1 H), 8.46 (d, J = 3.6 Hz, 1 H). 13C NMR (68 MHz, CDCl3):
d = 56.06, 112.15, 116.88, 118.31, 120.18, 121.93, 132.63, 134.73,
139.37, 148.61, 158.24, 160.21, 163.73. MS: m/z (%) = 229 (1)
[M+], 198 (12), 136 (11), 135 (100) [M+ – PyO], 77 (19). HRMS:
m/z calcd for C13H11NO3 [M+]: 229.0739; found: 229.0742.
4-Methoxybenzenepropanoic Acid 2-Pyridinyl Ester (30)
Colorless oil. Rf = 0.37 (hexane–EtOAc, 1:1). IR (KBr): nmax
=
2935, 2837, 1763, 1732, 1612, 1591, 1514, 1468, 1433, 1371, 1230,
1248, 1180, 1126, 1036, 997, 930, 827, 771, 739, 706, 623, 540,
513, 415 cm–1. 1H NMR (270 MHz, CDCl3): d = 2.90 (t, J = 6.9 Hz,
2 H), 3.03 (t, J = 6.9 Hz, 2 H), 3.80 (s, 3 H), 6.86 (d, J = 8.6 Hz, 2
H), 7.01 (d, J = 8.2 Hz, 1 H), 7.17–7.26 (m, 3 H), 7.77 (dd, J = 7.7,
1.6 Hz, 1 H), 8.40 (d, J = 3.3 Hz, 1 H). 13C NMR (68 MHz, CDCl3):
d = 29.76, 36.25, 55.17, 113.90, 116.36, 121.98, 129.28, 132.00,
139.41, 148.51, 157.77, 158.11, 170.99. MS: m/z (%) = 257 (3)
[M+], 180 (10), 135 (13), 134 (100), 121 (95), 96 (11). HRMS:
m/z calcd for C15H15NO3 [M+]: 257.1052; found: 257.1044.
3-Acetoxy-2-methylbenzoic Acid 2-Pyridinyl Ester (22)
White solid; mp 72 °C. Rf = 0.31 (hexane–EtOAc, 1:1). IR (KBr):
nmax = 3444, 2929, 1766, 1732, 1591, 1574, 1468, 1431, 1379,
Tricyclo[3,3,1,13,7]decane-1-carboxylic Acid 2-Pyridinyl Ester
(32)
White solid, mp 71 °C. Rf = 0.54 (hexane–EtOAc, 1:1). IR (KBr):
1257, 1223, 1196, 1146, 1024, 933, 920, 833, 785, 760, 748, 712,
607 cm–1. 1H NMR (270 MHz, CDCl3): d = 2.32 (s, 3 H), 2.45 (s, 3
H), 7.14 (d, J = 8.3 Hz, 1 H,), 7.21–7.33 (m, 3 H), 7.80 (dt, J = 7.9,
2.0 Hz, 1 H), 8.07 (dd, J = 7.6, 1.3 Hz, 1 H), 8.43 (dd, J = 5.0, 1.7
Hz, 1 H). 13C NMR (68 MHz, CDCl3): d = 13.53, 20.74, 116.62,
122.15, 126.32, 126.92, 129.15, 129.97, 133.69, 139.56, 148.70,
149.95, 158.05, 164.81, 169.07. MS: m/z (%) = 271 (1) [M+], 177
(56), 135 (100) [M+ – PyO], 134 (11), 107 (15), 106 (12), 79 (11),
78 (22), 77 (31), 52 (14), 51 (18). Anal. Calcd for C15H13NO4
C13H9NO3 (271.27): C, 66.41; H, 4.83; N, 5.16. Found: C, 66.12; H,
4.67; N, 5.09.
nmax = 2908, 2850, 1743, 1651, 1593, 1572, 1541, 1468, 1431,
1344, 1294, 1196, 1178, 1097, 1053, 993, 906, 854, 818, 771, 756,
729, 679, 623 cm–1. 1H NMR (270 MHz, CDCl3): d = 1.77 (s, 6 H),
2.09 (s, 9 H), 7.03 (d, J = 8.3 Hz, 1 H), 7.20 (dd, J = 7.3, 5.3 Hz, 1
H), 7.77 (dt, J = 7.8, 1.8 Hz, 1 H), 8.41 (dd, J = 4.9, 1.8 Hz, 1 H).
13C NMR (68 MHz, CDCl3): d = 27.82, 36.37, 38.57, 116.45,
121.73, 139.30, 148.57, 158.44, 175.79. MS: m/z (%) = 257 (11)
[M+], 136 (10), 135 (100) [M+ – COOPy], 107 (10), 96 (10), 93 (19),
91 (12), 79 (35), 77 (13), 67 (12). Anal. Calcd for C18H19NO2
(257.33): C, 74.68; H, 7.44; N, 5.44. Found: C, 74.62; H, 7.29; N,
5.24.
1,4-Benzenedicarboxylic Acid 2-Pyridinyl Ester (24)
White solid; mp 183 °C. Rf = 0.20 (hexane–EtOAc, 1:1). IR (KBr):
n
max = 3452, 3099, 3068, 1728, 1591, 1570, 1475, 1467, 1431,
References
1406, 1265, 1194, 1084, 1012, 993, 893, 868, 841, 775, 744, 715,
611 cm–1. H NMR (270 MHz, CDCl3): d = 7.23–7.34 (m, 4 H),
1
(1) (a) Rosenmund, K. W. Ber. Dtsch. Chem. Ges. 1918, 51,
585. (b) Rachlin, A. I.; Gurien, H.; Wagner, D. P. Org.
Synth., Coll. Vol. VI 1988, 1007.
7.89 (t, J = 7.6 Hz, 2 H), 8.37 (s, 4 H), 8.49 (d, J = 4.3 Hz, 2 H). 13
C
NMR (68 MHz, CDCl3): d = 116.39, 122.32, 130.34, 133.52,
139.59, 148.59, 157.71, 163.68. MS: m/z (%) = 320 (0) [M+], 292
(19), 226 (56) [M+ – PyO], 199 (13), 198 (100), 170 (19), 104 (72),
103 (15), 78 (15), 76 (70), 75 (24), 66 (11), 51 (15), 50 (29). HRMS:
m/z calcd for C18H12N2O4 [M+]: 320.0797; found: 320.0799.
(2) For reviews on the Rosenmund reduction, see: (a)Mosettig,
E.; Mozingo, R. Org. React. 1948, 4, 362. (b)Larsen, R. D.;
King, A. O. In Handbook of Organopalladium Chemistry
for Organic Synthesis, Vol. 2; Negishi, E., Ed.; John Wiley
and Sons: New York, 2002, Chap. VI.2.4, 2473.
(3) Citron, J. D. J. Org. Chem. 1969, 34, 1977.
(4) Four, P.; Guibe, F. J. Org. Chem. 1981, 46, 4439.
(5) (a) Fukuyama, T.; Lin, S.-C.; Li, L. J. Am. Chem. Soc. 1990,
112, 7050. (b) Kanda, Y.; Fukuyama, T. J. Am. Chem. Soc.
1993, 115, 8451. (c) Fujiwara, A.; Kan, T.; Fukuyama, T.
Synlett 2000, 1667. (d) Tokuyama, H.; Yokoshima, S.; Lin,
S.-C.; Li, L.; Fukuyama, T. Synthesis 2002, 1121.
(e) Fukuyama, T.; Tokuyama, H. Aldrichimica Acta 2004,
37, 87.
1-Naphthalenecarboxylic Acid 2-Pyridinyl Ester (26)
White solid; mp 92 °C. Rf = 0.43 (hexane–EtOAc, 1:1). IR (KBr):
n
max = 3423, 3005, 1722, 1591, 1570, 1510, 1464, 1431, 1396,
1281, 1245, 1207, 1194, 1119, 982, 885, 827, 787, 754, 660, 625,
600, 505 cm–1. H NMR (270 MHz, CDCl3): d = 7.26–7.33 (m, 2
1
H), 7.54–7.69 (m, 3 H), 7.87 (dd, J = 7.6, 2.0 Hz, 1 H), 7.93 (d,
J = 8.2 Hz, 1 H), 8.12 (d, J = 8.2 Hz, 1 H), 8.51 (dd, J = 4.9, 2.0 Hz,
1 H), 8.56 (dd, J = 7.4, 1.1 Hz, 1 H), 9.08 (d, J = 8.6 Hz, 1 H). 13
C
NMR (68 MHz, CDCl3): d = 116.95, 122.23, 124.62, 125.29,
125.84, 126.54, 128.39, 128.81, 131.87, 131.89, 134.01, 134.81,
139.68, 148.87, 158.44, 165.41. MS: m/z (%) = 249 (5) [M+], 156
(12), 155 (100) [M+ – PyO], 127 (76), 126 (14), 77 (11). Anal. Calcd
for C16H11NO2 (249.26): C, 77.10; H, 4.45; N, 5.62. Found: C,
76.94; H, 4.42; N, 5.57.
(6) Kimura, M.; Seki, M. Tetrahedron Lett. 2004, 45, 3219.
(7) (a) Nagayama, K.; Kawataka, F.; Sakamoto, M.; Shimizu, I.;
Yamamoto, A. Bull. Chem. Soc. Jpn. 1999, 72, 573.
(b) Nagayama, K.; Shimizu, I.; Yamamoto, A. Bull. Chem.
Soc. Jpn. 2001, 74, 1803.
(8) Gooben, L. J.; Ghosh, K. Chem. Commun. 2002, 836.
(9) Tatamidani, H.; Kakiuchi, F.; Chatani, N. Org. Lett. 2004, 6,
3597.
(10) Harada, Y.; Fukumoto, Y.; Chatani, N. Org. Lett. 2005, 7,
4385.
3-(4-Methoxyphenyl)-2-propenoic Acid 2-Pyridinyl Ester (28)
White solid; mp 101 °C. Rf = 0.40 (hexane–EtOAc, 1:1). IR (KBr):
n
max = 2962, 2839, 1722, 1633, 1599, 1514, 1471, 1425, 1333,
1309, 1257, 1221, 1174, 1128, 1026, 991, 926, 866, 833, 808, 762,
741, 530, 513 cm–1. 1H NMR (270 MHz, CDCl3): d = 3.85 (s, 3 H),
Synlett 2006, No. 6, 869–872 © Thieme Stuttgart · New York