COMMUNICATIONS
References and Notes
Benjamin List et al.
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thesis: A. K. Chatterjee, F. D. Toste, T.-L. Choi, R. H.
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9
[4] a) For aromatic aldehydes, see: A. Galat, J. Am. Chem.
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[
2] For other approaches to a,b-unsaturated esters from al-
dehydes, see: a) Claisen–Schmidt-type condensation of
aromatic aldehydes: M. Hatsuda, T. Kuroda, M. Seki,
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[5] Aldrich catalogue: (carbethoxymethylene)triphenyl-
2
phosphorane (3, R ¼Et), 10 mmol ca. EUR 17.00,
2
triethyl phosphonoacetate (4, R ¼Et), 10 mmol ca.
2
1
641–1643; B. E. Ledford, E. M. Carreira, Tetrahedron
EUR 2.00, monoethyl malonate (7, R ¼Et) 10 mmol
Lett. 1997, 38, 8125–8128; M.-Y. Lee, Y. Chen, X. P.
Zhang, Organometallics 2003, 22, 4905–4909; c) from
ca. EUR 5.00, monoethyl malonate, potassium salt
10 mmol ca. EUR 2.00.
methyl dichloroacetate and stoichiometric CrCl : D. K.
[6] For the preparation of the ethylmalonic acid and of its
potassium salt from diethyl malonate (10 mmol ca.
EUR 0.60), see: M. E. Hediger, Bioorg. Med. Chem.
2004, 12, 4995–5010.
2
Barma, A. Kundu, A. Bandyopadhyay, A. Kundu, B.
Sangras, A. Briot, C. Mioskowski, J. R. Falck, Tetrahe-
dron Lett. 2004, 45, 5917–5920; d) via Peterson-type ole-
fination with ethyl (trimethylsilyl)acetate: H. Taguchi, K.
Shimoji, H. Yamamoto, H. Nozaki, Bull. Chem. Soc. Jpn.
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fluence of heteroaromatic amines on Knoevenagel con-
densation: H. Yamanaka, M. Yokoyama, T. Sakamoto,
T. Shiraishi, M. Sagi, M. Mizugaki, Heterocycles 1983,
20, 1541–1544; d) for mechanistic studies on this subject,
see: E. J. Corey, J. Am. Chem. Soc. 1952, 74, 5897–5905;
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[8] In one report DMAPhas been used as a catalyst for the
reaction of malonic acid half esters with a,b-unsaturated
aldehydes at elevated temperature in pyridine to give the
corresponding a,b,g,d-unsaturated esters, see: J. Rodri-
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1
974, 47, 2529–2531; e) from mercaptoacetates: S. Matui,
K. Tanaka, A. Kaji, Synthesis 1983, 2, 127–128; f) from
ethyl bromoacetate and n-Bu Sb: Y. Huang, Y. Shen, C.
3
Chen, Tetrahedron Lett. 1986, 27, 2903–2904; g) from
ethyl bromoacetate and n-Bu Te: X. Huang, L. Xie, H.
2
Wu, Tetrahedron Lett. 1987, 28, 801–802; h) from ethyl
bromoacetate in the presence of a Te-catalyst, potassium
carbonate, sodium bisulfite, and triphenyl phosphite:
Z. Z. Huang, S. Ye, W. Sia, Y. Tang, Chem. Commun.
2
001, 15, 1384–1385; i) from a-chloroacetaldehyde dia-
lkyl acetal via alkoxyacetylide anions: G. A. Olah,
A. H. Wu, O. Farooq, G. K. Prakash, Synthesis 1988, 7,
5
37–538; j) from orthoacetates: H. M. Sapath Kumar,
M. Shesha Rao, S. Joyasawal, J. S. Yadav, Tetrahedron
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thanesulfonyl fluoride: S. Kagabu, C. Shimizu, J. Takaha-
shi, K. Hara, M. Koketsu, M. Ishida, Bull. Soc. Chim. Fr.
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List, in: Modern Aldol Reactions, Vol. 1, (Ed.: R. Mahr-
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200.
1
992, 129, 435–439; l) from ethyl (benzothiazol-2-ylsul-
fonyl)acetate: P. R. Blakemore, D. K. H. Ho, W. M. [10] Studiengesellschaft Kohle mbH, Process for the produc-
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tion of olefins from carbonyl compounds. Patent pending.
[3] For selected alternative approaches to a,b-unsaturated
esters, see: a) Heck reaction: I. P. Beletskaya, A. V. Che-
1560
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