- N-Heterocyclic Carbene-Catalyzed Umpolung of Alkynyl 1,2-Diketones
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The umpolung of alkynyl 1,2-diketones via N-heterocyclic carbene (NHC) catalysis was achieved for the first time, allowing the rapid access to a large variety of synthetically and pharmaceutically important α-pyrones under very mild conditions. A completely new NHC-catalyzed umpolung pattern involving an O-acylated allenolate as the key intermediate was proposed. Moreover, an unprecedented reaction pathway, featured by a series of group migrations and new bond formation, was postulated to demonstrate the formation of the products. (Figure presented.).
- Kong, Xiangwen,Zhang, Guoxiang,Yang, Shuang,Liu, Xiaozhi,Fang, Xinqiang
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supporting information
p. 2729 - 2734
(2017/08/23)
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- Synthesis and reactivity of Z and E functionalized allylic fluorides
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The allylic fluorides 1 and 2 are used as models to study the effect of the allylic C-F bond on the diastereoselectivity of reactions occurring on the vicinal double bond, as well as the compatibility of this C-F bond with various reagents. The configurational stability of the Z double bonds in enals and enones 1 and 3 is noteworthy. This allowed us to perform various types of reactions (including thermal Diels-Alder cycloadditions) on derivatives 1 with full control of the Z geometry.
- Prakesch, Micha?l,Grée, Danielle,Grée, René
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p. 8833 - 8841
(2007/10/03)
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