Palladium-catalyzed carbonylative coupling of organolead compounds: Synthesis of symmetrical ketones

Article abstract of DOI:10.1081/SCC-100103533

Organolead acetates can be carbonylated in the presence of Pd₂(dba)₃·CHCl₃ (5mol%) and NaOMe (5 equiv.) in CH₃CN under atmospheric pressure of carbon monoxide at room temperature to afford symmetrical ketones.

Full text of DOI:10.1081/SCC-100103533

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PALLADIUM-CATALYZED
CARBONYLATIVE COUPLING
OF ORGANOLEAD
COMPOUNDS: SYNTHESIS OF
SYMMETRICAL KETONES
a
a
Suk-Ku Kang , Hyung-Chul Ryu & Sang-Chul Choi
a
a
Department of Chemistry , Sungkyunkwan
University , Natural Science Campus, Suwon,
400-746, Korea
Published online: 09 Nov 2006.
To cite this article: Suk-Ku Kang , Hyung-Chul Ryu & Sang-Chul Choi (2001)
PALLADIUM-CATALYZED CARBONYLATIVE COUPLING OF ORGANOLEAD COMPOUNDS:
SYNTHESIS OF SYMMETRICAL KETONES, Synthetic Communications: An International
Journal for Rapid Communication of Synthetic Organic Chemistry, 31:7, 1035-1039,
DOI: 10.1081/SCC-100103533
To link to this article: http://dx.doi.org/10.1081/SCC-100103533
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SYNTHETIC COMMUNICATIONS, 31(7), 1035–1039 (2001)
PALLADIUM-CATALYZED
CARBONYLATIVE COUPLING
OF ORGANOLEAD COMPOUNDS:
SYNTHESIS OF SYMMETRICAL
KETONES
Suk-Ku Kang,* Hyung-Chul Ryu, and Sang-Chul Choi
Department of Chemistry, Sungkyunkwan University,
Natural Science Campus, Suwon 400-746, Korea
ABSTRACT
Organolead acetates can be carbonylated in the presence
of Pd (dba) ꢀCHCl (5 mol%) and NaOMe (5 equiv.) in
2
3
3
CH CN under atmospheric pressure of carbon monoxide at
3
room temperature to afford symmetrical ketones.
The palladium-catalyzed carbonylative coupling of electrophiles with
organometallic compounds, such as organostannanes, boron, aluminium,
1
and zinc is an important method for the synthesis of ketones. Recently,
2
Jackson et al. reported the synthesis of symmetrical ketones via palladium-
3
catalyzed carbonylation of organozinc species. It is known that CoBr (1.5
2
equiv.)-mediated carbonylation of organozinc reagents leads to symmetrical
polyfunctional ketones. Here we report the palladium-catalyzed carbonyla-
4
tion of organolead acetates leading to symmetrical ketones (Scheme 1).
*
Corresponding author.
1
035
Copyright & 2001 by Marcel Dekker, Inc.
www.dekker.com

1
036
KANG, RYU, AND CHOI
Scheme 1.
The palladium-catalyzed carbonylative coupling of organolead acetates
is summarized in Table 1. When the phenyllead triacetate (1a) reacted with
carbon monoxide (1 atm) in the presence of Pd (dba) ꢀCHCl (5 mol%) and
2
3
3
NaOMe (5 equiv.) in acetonitrile for 3 h at room temperature, benzophe-
none (2a) was afforded in 70% yield (entry 1 in Table 1). The addition of
5
NaOMe is critical. Under the same conditions the reaction of p-tolyllead
triacetate (1b) gave the dimerized ketone 2b in 70% yield (entry 2). The
p-methoxyphenyllead triacetate (1c) was readily coupled with carbon
6
monoxide (1 atm) to provide the symmetrical ketone 2c in 72% yield
(
triacetate (1e) were subjected to carbonylative coupling to afford the sym-
entry 3). The 2,4-dimethoxyphenyllead triacetate (1d) and 2-thienyllead
7
metrical ketones 2d and 2e in 69% and 85% yields, respectively (entries 4
and 5). For di(2-furyl)lead diacetate (1f) the carbonylative coupling gave the
8
ketone 2f in 74% yield (entry 6). This method was extended to alkenyllead
triacetate (1g) and treatment of 1g with carbon monoxide (1 atm) in the
presence ofPdCl (5 mol%)as catalystaffordedthetrans,trans-dibenzylidene-
acetone (2g) in 71% yield (entry 7).
2
Although the detailed mechanism for the formation of diaryl ketones
remains obscure, it is presumed that organolead trimonoxide RPb(OMe)3
is formed and drives facile oxidative addition with Pd(0) to give polar
and reactive intermediate RPdPb(OMe) , followed by carbonylation reac-
3
tion to furnish RCOPdPb(OMe) , which allows the transmetallation
3
with RPb(OMe) to afford RCOR. In summary, the palladium-catalyzed
3
carbonylative coupling of organolead compounds afforded the symmetrical
ketones.
EXPERIMENTAL
Typical Procedures
Preparation of Bis-2-thiophenylmethanone (2e)
To a stirred solution of Pd (dba) CHCl (26mg, 0.026mmol), and
2
3
3
NaOMe (138 mg, 2.56mmol) in dry CH CN (25 mL) under atmospheric
3
pressure of carbon monoxide was added 2-thienyllead triacetate (1e)
(
240 mg, 0.52 mmol) at room temperature. The reaction mixture was stirred

SYMMETRICAL KETONES
1037
Table 1. The Palladium Catalyzed Carbonylative Coupling of Organolead Acetates
Organolead
Compounds
Isolated
Yield (%)
Entry
1
Product
70
70
1
1
a
b
2a
2
3
2b
2c
72
69
1
c
4
1
d
2d
2e
5
6
85
1
e
74z
1
f
2f
a
71
7
1
g
2g
a
PdCl (5 mol%) was used as a catalyst.
2
at room temperature for 3 h and extracted with diethyl ether (20 mL ꢁ 3).
The organic layer was dried over anhydrous sodium sulfate and the solvent
was evaporated in vacuo. The crude product was separated by SiO column
2
chromatography (EtOAc/hexanes 1 : 10, R ¼ 0.38) to afford the coupled
f
product 2e (42 mg, 85%). TLC, SiO , EtOAc/hexanes 1 : 10, R ¼ 0.38.
2
f

1
038
KANG, RYU, AND CHOI
ꢂ
ꢂ
1
m.p. 90 ꢃ 90.5 C H NMR (400 Hz, CDCl ) ꢀ 7.18 (dd, 2H, J ¼ 4.2,
3
0
.7 Hz), 7.69 (dd, 2H, J ¼ 4.2, 0.7 Hz), 7.89 (dd, 2H, J ¼ 2.7, 1.1 Hz). IR
À1
(
KBr) 3055, 2986, 1650, 1617, 1412, 1265 cm . MS (EI) m/e (relative
þ
intensity) ¼ 195 (M ), 194 (73), 95 (100), 78 (11).
Di-p-tolyl-methanone (2b)
ꢂ
ꢂ
1
TLC, SiO , EtOAc/hexanes 1 : 10, R ¼ 0.40. m.p. 90 ꢃ93 C H NMR
2
f
(
400 Hz, CDCl ) ꢀ 2.44 (s, 3H), 7.26(d, 2H, J ¼ 1.5 Hz), 7.70 (dd, 2H,
3
À1
J ¼ 5.0, 1.5 Hz). IR (KBr) 3055, 2986, 1652, 1607, 1418, 1266 cm
.
þ
MS (EI) m/e (relative intensity) ¼ 210 (M ), 195 (21), 119 (100), 91 (30).
Bis-(4-methoxyphenyl)methanone (2c)
ꢂ
ꢂ
TLC, SiO , EtOAc/hexanes 1 : 10, R ¼ 0.25. m.p. 141 –143 C
2
f
1
H NMR (400 Hz, CDCl ) ꢀ 3.88 (s, 3H), 6.97 (m, 2H), 7.78 (m, 2H).
IR (KBr) 3052, 1650, 1408 cm . MS (EI) m/e (relative intensity) ¼ 242
3
À1
(
12), 135 (100), 92 (20), 77 (25).
Bis-(2,4-dimethoxyphenyl)methanone (2d)
1
TLC, SiO , EtOAc/hexanes 1 : 10, R ¼ 0.26. H NMR (400 Hz,
2
f
CDCl ) ꢀ 3.60 (s, 3H), 3.82 (s, 3H), 6.42 (d, 1H, J ¼ 2.2 Hz), 6.49 (dd, 1H,
3
J ¼ 2.2, 8.4 Hz), 7.49 (d, 1H, J ¼ 8.4 Hz). IR (KBr) 3117, 3056, 2934, 1630,
À1
þ
1
(
3
603, 1408, 1265 cm . MS (EI) m/e (relative intensity) ¼ 302 (M , 33), 284
17 18 5
59), 164 (100), 150 (28). HRMS calcd for C H O : 302.1147, found:
02.1154.
Bis-2-furylmethanone (2f)
TLC, SiO , EtOAc/hexanes 1 : 10, R ¼ 0.34. m.p. 30 ꢃ32 C H NMR
ꢂ
ꢂ
1
2
f
(
400 Hz, CDCl ) ꢀ 6.60 (dd, 2H, J ¼ 3.0, 1.7 Hz), 7.55 (dd, 2H, J ¼ 3.0,
3
0
1
7
.6Hz), 7.68 (dd, 2H, J ¼ 1.7, 0.6 Hz). IR (KBr) 3134, 1633, 1467,
À1 þ
402 cm . MS (EI) m/e (relative intensity) ¼ 163 (M ), 162 (73), 95 (100),
8 (11).

SYMMETRICAL KETONES
1039
1
,5-Diphenyl-penta-1,4-dien-3-one (2g)
ꢂ
ꢂ
TLC, SiO , EtOAc/hexanes 1 : 10, R ¼ 0.33. m.p. 104 ꢃ107 C
2
f
1
H NMR (400 Hz, CDCl ) ꢀ 7.10 (d, 1H, J ¼ 16Hz), 7.41 (m, 3H), 7.60
3
(
1
1
m, 2H), 7.55 (d, 1H, J ¼ 16 Hz). IR (KBr) 3055, 2987, 2860, 1654, 1620,
À1
þ
265 cm . MS (EI) m/e (relative intensity) ¼ 235 (M ), 234 (100), 233 (90),
31 (39), 103 (57), 77 (48).
ACKNOWLEDGMENTS
Generous financial support from KOSEF-Center for Molecular
Design and Synthesis (CMDS) is gratefully acknowledged.
REFERENCES AND NOTES
1
2
. For a recent book on palladium-catalyzed reaction: Tsuji, J. In
Palladium Reagents and Catalysts, Innovations in Organic Synthesis
John Wiley & Sons: New York, 1995.
. Jackson, R.F.W.; Turner, D.; Block, M.H. J. Chem. Soc., Perkin Trans. 1
1
. Devasagayaraj, A.; Knochel, P. Tetrahedron Lett. 1995, 36, 8411–8414.
. Recently, Pinhey reported the arylation and alkenylation of organolead
(IV) compounds with soft carbon nucleophiles: Pinhey, J.T. Pure &
Appl. Chem. 1996, 68, 819–824. We have reported the cross-coupling
997, 865–870.
3
4
of organolead compounds: Kang, S.K.; Ryu, H.C.; Son, H.J. Synlett
1
998, 771–773.
5
. Without adding NaOMe, the substituted lead (IV) triacetate underwent
homocoupling. Kang, S.K.; Shivakuma, U.; Ahn, C.J.; Choi, S.C.;
Kim, J.S. Synth. Commun. 1997, 27, 1893–1897.
6
7
. Yasui, K.; Tanaka, S.; Tamaru, Y. J. Org. Chem. 1995, 60, 1365–1380.
. Strekovski, L.; Wyara, R.L.; Cegla, M.T.; Czarny, A.; Patterson, S.
J. Org. Chem. 1989, 54, 6120–6123.
8
. Boyle, P.H.; Cocker, W.; McMurry, T.B.H.; Pratt, C.A. J. Chem. Soc. C.
1
967, 1993.
Accepted May 8, 2000