E. S. Kim et al. / Tetrahedron Letters 50 (2009) 2973–2975
Ph-CN (1a)
2975
PdII
[PdII]
CH3CN
Ph
C N
PhCONH2 (2a)
CH3CH=NOH
H
N
Me
H
[PdII]
Ph
N
O
(I)
Scheme 2.
Tyler, D. R. Organometallics 2003, 22, 1203–1211; (k) Kim, J. H.; Britten, J.; Chin,
J. J. Am. Chem. Soc. 1993, 115, 3618–3622; (l) Chin, J.; Kim, J. H. Angew. Chem.,
Int. Ed. 1990, 29, 523–525; (m) Leung, C. W.; Zheng, W.; Zhou, Z.; Lin, Z.; Lau, C.
P. Organometallics 2008, 27, 4957–4969.
Acknowledgments
This work was supported by the Korea Research Foundation
Grant funded by the Korean Government (MOEHRD, KRF-2008-
313-C00487). Spectroscopic data was obtained from the Korea Ba-
sic Science Institute, Gwangju branch.
4. For the Pd-catalyzed hydration of nitriles to amides, see: (a) Villain, G.; Kalck,
P.; Gaset, A. Tetrahedron Lett. 1980, 21, 2901–2904; (b) McKenzie, C. J.; Robson,
R. J. Chem. Soc., Chem. Commun. 1988, 112–114.
5. (a) Maffioli, S. I.; Marzorati, E.; Marazzi, A. Org. Lett. 2005, 7, 5237–5239; (b)
Neugebauer, R. C.; Uchiechowska, U.; Meier, R.; Hruby, H.; Valkov, V.; Verdin,
E.; Sippl, W.; Jung, M. J. Med. Chem. 2008, 51, 1203–1213.
6. Kim, H. S.; Kim, S. H.; Kim, J. N. Tetrahedron Lett. 2009, 50, 1717–1719. and
further references cited therein. During the previous Pd-catalyzed dehydration
reaction of 4-nitrobenzaldoxime in CD3CN in NMR tube, we observed the
formation of CD3CONH2 (unpublished results).
7. In the reaction, acetamide was isolated in 42% and the results stated that
acetaldoxime was converted into acetonitrile and acetamide. Actually, when
the reaction of acrylonitrile (1g) was carried out in D2O in NMR tube we
observed the formation of acrylamide (2g), acetonitrile, and acetamide, and
acetaldoxime disappeared completely.
8. Typical procedure for the synthesis of benzamide: A mixture of benzonitrile (1a,
206 mg, 2.0 mmol), acetaldoxime (236 mg, 4.0 mmol), Pd(OAc)2 (45 mg,
10 mol %), and PPh3 (105 mg, 20 mol %) in aqueous EtOH (H2O/EtOH, 1:4,
3 mL) was heated to reflux for 3 h under nitrogen atmosphere. The reaction
mixture was filtered through a Celite pad and washed with EtOH/CH2Cl2. After
removal of solvent and column chromatographic purification process (hexanes/
EtOAc/CHCl3, 1:1:1) benzamide (2a) was obtained as a white solid, 216 mg
(89%). The synthesized compounds were identified by comparing the melting
points with the reported ones and we characterized the structure by their 1H
NMR and/or IR in some cases.
9. (a) Bertani, R.; Gotti, M.; Michelin, R. A.; Mozzon, M. Organometallics 1996,
15, 1236–1241; (b) Ruiz, J.; Rodriguez, V.; Lopez, G. Organometallics 1999,
18, 1177–1184; (c) Ruiz, J.; Cutillas, N.; Rodriguez, V.; Sampedro, J.; Lopez,
G.; Chaloner, P. A.; Hitchcock, P. B. J. Chem. Soc., Dalton Trans. 1999, 2939–
2946.
References and notes
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10. Hydration of 1a with 3 mol % Pd(PPh3)4 in the presence of actaldoxime
(2.0 equiv) in aqueous EtOH (reflux, 3 h) also produced 2a in a similar yield
(87%). The results stated that nitrile–oxime adduct could also be generated by
the nucleophilic attack of acetaldoxime to activated benzonitrile by
coordination-unsaturated low-valent Pd species.