Categories: Synthesis of O-Heterocycles >
Synthesis of 3(2H)-furanones
A catalyst generated from the combination of (p-CF3C6H4)3PAuCl and AgOTf cyclizes readily available γ-hydroxyalkynones under mild conditions to give substituted 3(2H)-furanones in good yields. This method is also applicable to the preparation of 2,3-dihydro-4H-pyran-4-ones.
M. Egi, K. Azechi, M. Saneto, K. Shimizu, S. Akai, J. Org. Chem., 2010, 75, 2123-2126.
A simple protocol for the efficient synthesis of 3(2H)-furanones by cycloisomerization of allenic hydroxyketones is achieved in water and in the absence of any expensive metal catalysts.
M. Poonoth, N. Krause, J. Org. Chem., 2011, 76, 1934-1936.
A novel approach to 3(2H)-furanones combines a transition-metal-catalyzed activation of alkynes with a heterocyclization and subsequent 1,2-alkyl shift. Starting 2-hydroxy-2-alkynylcarbonyl compounds can be prepared by simple oxygenation of alkynyl carbonyl compounds using 2-iodoxybenzoic acid (IBX).
S. F. Kirsch, J. T. Binder, C. Liébert, H. Menz, Angew. Chem. Int. Ed., 2006, 45, 5878-5880.
An unexpected facile domino reaction of α,β-acetylenic γ-hydroxy nitriles with arenecarboxylic acids affords 4-cyano-3(2H)-furanones in good yield. The reaction is triggered by the addition of an arenecarboxylic acid to a triple bond, followed by intramolecular transesterification-enol formation and Claisen condensation of the ketoacetonitrile tautomer with ester functional group.
B. A. Trofimov, O. A. Shemyakina, A. G. Mal'kina, I. A. Ushakov, O. N. Kazheva, G. G. Alexandrov, O. A. Dyachenko, Org. Lett., 2010, 12, 3200-3203.
A facile alkylative intramolecular cyclization of 3-alkoxycarbonyl-2-oxopropyldiphenylsulfonium salts provides 4-alkylated 3(2H)-furanones in good yields under mild conditions.
S. Inagaki, M. Ukaku, A. Chiba, F. Takahashi, Y. Yoshimi, T. Morita, T. Kawano, J. Org. Chem., 2016, 81, 8363-8369.
Gold-catalyzed cyclizations of 2-oxo-3-butynoic esters or disubstituted-1,2-diones with a variety of nucleophiles offer an efficient and straightforward route to substituted 3(2H)-furanones under mild reaction conditions.
Y. Liu, M. Liu, S. Guo, H. Tu, Y. Zhou, H. Gao, Org. Lett., 2006, 8, 3445-3448.
A sequence consisting of an electrophilic cyclization in the presence of N-iodosuccinimide (NIS) and an 1,2-migration allows the construction of 4-iodo-3-furanones from 2-alkynyl-2-silyloxy carbonyl compounds. In a more versatile variant, AuCl3 catalyzes the tandem reaction in the presence of NIS to provide highly substituted heterocycles in good yields.
B. Crone, S. F. Kirsch, J. Org. Chem., 2007, 72, 5435-5438.