Categories: C-C Bond Formation > Oxygen-containing molecules >
Synthesis of β-keto carboxylic acids, esters and amides
Name Reactions
Recent Literature
Mild and Efficient Pentafluorophenylammonium Triflate (PFPAT)-Catalyzed
C-Acylations of Enol Silyl Ethers or Ketene Silyl (Thio)Acetals with Acid
Chlorides
A. Iida, J. Osada, R. Nagase, T. Misaki, Y. Tanabe, Org. Lett., 2007,
9, 1859-1862.
A Ti-crossed Claisen condensation between ketene silyl (thio)acetals and acid chlorides gave
α-monoalkylated (thio)esters and thermodynamically unfavorable
α,α-dialkylated β-keto (thio)esters in good yield. The protocol was extended to the
direct condensation of ketene silyl acetals with carboxylic acids.
A. Iida, S. Nakazawa, T. Okabayashi, A. Horii, T. Misako, Y. Tanabe, Org. Lett., 2006,
8, 5215-5218.
A. Iida, S. Nakazawa, T. Okabayashi, A. Horii, T. Misako, Y. Tanabe, Org. Lett., 2006,
8, 5215-5218.
Thioesters undergo chemoselective soft enolization and acylation by N-acylbenzotriazoles
on treatment with MgBr2ˇOEt2 and i-Pr2NEt
to give β-keto thioesters without prior enolate formation. The reaction is
conducted using untreated CH2Cl2 open to the air. The
coupled products can be converted directly into β-keto esters, β-keto amides,
and β-diketones under mild conditions.
G. Zhou, D. Lim, D. M. Coltart, Org. Lett.,
2008,
10, 3809-3812.
Aromatic, aliphatic, and heterocyclic aldehydes are successfully condensed with
ethyl diazoacetate in the presence of molybdenum(VI) dichloride dioxide as
catalyst to obtain the corresponding β-keto esters in high yields at room
temperature.
K. Jeyakumar, D. K. Chand, Synthesis, 2008,
1685-1687.
Aldehydes react readily with ethyl diazoacetate in the presence of 5 mol% of
NbCl5 in dichloromethane to produce the corresponding β-keto esters in good
yields with high selectivity. This method allows the preparation of
β-keto esters from various
aldehydes under mild reaction conditions.
J. S. Yadav, B. V. S. Reddy, B. Eeshwaraiah, P. N. Reddy, Tetrahedron, 2005,
61, 875-878.
The TiCl4-mediated reaction of esters with benzoyl chloride
gave α-benzoylated esters in high yields.
D. F. Taber, R. B. Sheth, P. V. Joshi, J. Org. Chem., 2005,
70, 2851-2854.
A convenient two-step preparation of alkylidenepyrrolidines is reported.
M. C. Elliot, S. V. Wordingham,
Synthesis, 2006, 1162-1170.
