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Prof. Maulide: Gold-Catalyzed Synthesis of Furans and Furanones from Sulfonium Ylides
The group of Professor Nuno Maulide (University of Vienna) works on development and understanding of unconventional reactions in organic chemistry. TCI is pleased to introduce their recent study on gold-catalyzed Synthesis of Furans and Furanones from Sulfonium Ylides:
(We thank Prof. Maulide for writing the abstract, for full article please refer to the link underneath)
Gold-Catalyzed Synthesis of Furans and Furanones from Sulfonium Ylides
Angew. Chem. Int. Ed. 2012,51, 8886-8890 and Angew. Chem. 2012, 124, 9016-9020
Introduction:
Polysubstituted furan derivatives are fundamental building blocks in organic synthesis and find wide representation among natural products, agrochemicals, and pharmaceuticals.[1] Herein, a simple and flexible gold-catalyzed synthesis of densely functionalized 3-carboxyfuran derivatives is reported. The starting materials, stabilized sulfonium ylides, are prepared by ylide transfer[2] employing Martin’s Sulfurane[3].
Scope:
1- Intramolecular synthesis of bicyclofurans:A variety of bicyclofurans could be readily prepared by simply stirring appropriate sulfonium ylide precursors in the presence of a gold catalyst at room temperature (Scheme 1).
2- Intermolecular Synthesis of furans:
Intermolecular furan synthesis by this procedure proved particularly sensitive to the substitution pattern of both the sulfonium ylide and the alkyne partner (Scheme 2). In the event, malonate-derived sulfonium ylides provided alkoxyfurans in reasonable efficiency.
3- Synthesis of -lactones from sulfonium ylides and alkynes :
Under the influence of Echavarren’s catalyst,[4] the use of allyloxyesters in conjunction with arylacetylenes afforded C-allylated 2-furanones carrying a quaternary center, along with the expected furan product (Scheme 3).
Conclusion:
A gold-catalyzed synthesis of heterocycles was developed from doubly-stabilized sulfonium ylides. This transformation is amenable to a reactivity switch triggered by modification of the electron-withdrawing moieties of the ylide partner, delivering either furans or furanones bearing a quaternary center as products.
Reference
- 1) - a) R. J. Sundberg in Comprehensive Heterocyclic Chemistry, Vol. 5. (Eds.: A. R. Katrzky, C. W. Rees), Pergamon, New York, 1984, p.313; b) H. N. C. Wong, X.-L. Hou, K.-S. Yeung, H. Huang in Five-membered Heterocycles: Furan, Vol. 1 (Eds.: J. Alvarez-Builla, J. J. Vaquero, J.Barluenga), Wiley-VCH, Weinheim, 2011, p. 533.
- 2) X. Huang, R. Goddard, N. Maulide, Angew. Chem. 2010, 122, 9163; Angew. Chem. Int. Ed. 2010, 50, 8979.
- 3) Martin’s Sulfurane, TCI Product B2200.
- 4) C. Nieto-Oberhuber, S. Lopez, M. P. Munoz, D. J. Cardenas, E. Bunuel, C. Nevado, A. M. Echavarren, Angew. Chem. 2005, 117, 6302; Angew. Chem. Int. Ed. 2005, 44, 6146.