Synthesis of 1,3-diketones
Ketones undergo soft enolate formation and acylation on treatment with MgBr2ˇOEt2, i-Pr2NEt, and various acylating agents to give 1,3-diketones. A particularly simple and efficient acylation with N-acylbenzotriazoles and O-Pfp esters can be conducted in untreated, reagent-grade CH2Cl2 open to the air.
D. Lim, F. Fang, G. Zhou, D. M. Coltart, Org. Lett., 2007, 9, 4139-4142.
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.
Treatment of an γ-acyloxy-α,β-unsaturated ketone with bis(iodozincio)methane leads to a novel tandem reaction consisting of three steps: 1,4-addition of the dizinc reagent to the enone, intramolecular nucleophilic attack by the enolate on the ester group, and Grob-type fragmentation of the adduct to give 1,3-diketones efficiently.
M. Sada, S. Matsubara, J. Am. Chem. Soc., 2010, 132, 432-433.
Substituted 1,3-diketones were synthesized from α,β-unsaturated ketones by treatment with acid chlorides and Et2Zn in the presence of RhCl(PPh3)3. The reaction offers a very simple and chemoselective acylation at the α-position of α,β-unsaturated ketones.
K. Sato, S. Yamazoe, R. Yamamoto, S. Ohata, A. Tarui, M. Omote, I. Kumadaki, A. Ando, Org. Lett., 2008, 10, 2405-2408.
A recyclable, convenient, and efficient catalytic system allows the C-acylation of 1,3-dicarbonyl compounds and malononitrile with acid chlorides in moderate to excellent yields under mild conditions.
Q. Shen, W. Huang, J. Wang, X. Zhou, Org. Lett., 2007, 9, 4491-4494.
Various 1,3,5-tricarbonyl derivatives were prepared by a mild reaction of 1,3-bis(silyl enol ethers) with acid chlorides. Reactions of both aromatic and aliphatic acid chlorides and bis(acid chlorides) were conducted.
T. Rahn, V. T. H. Nguyen, T. H. T. Dang, Z. Ahmed, K. Methling, M. Lalk, C. Fischer, A. Spannenberg, P. Langer, J. Org. Chem., 2007, 72, 1957-1961.
A short, mild, and highly chemoselective addition of organolithium reagents to BF2 complexes of 3-oxopropanoates allows a straightforward preparation 1,3-diketones.
B. Štefane, Org. Lett., 2010, 12, 2900-2903.