American Chemical Society
ol800740h_si_003.cif (13.24 kB)

Reversal of Nucleophilicity of Enamides in Water: Control of Cyclization Pathways by Reaction Media for the Orthogonal Synthesis of Dihydropyridinone and Pyrrolidinone Clausena Alkaloids

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Version 2 2016-06-03, 23:26
Version 1 2016-02-27, 11:32
posted on 2008-06-19, 00:00 authored by Luo Yang, Qi-Yu Zheng, De-Xian Wang, Zhi-Tang Huang, Mei-Xiang Wang
A highly efficient, metal-free, and divergent method for the synthesis of 3,4-dihydropyridin-2-one and pyrrolidin-2-one Clausena alkaloids and their analogs is reported. While the oxirane-containing enamides underwent the TFA-mediated 6-endo-enamide-epoxide cyclization reaction in ButOH to produce homoclausenamides, an unprecedented nucleophilic reaction occurred at the α-carbon of enamides in water to yield 5-endo-enamide-epoxide cyclization products in excellent yields. The reversal of nucleophilicity of enamides in intramolecular cyclization is discussed in terms of steric and electronic effects of the oxirane-containing enamides.