One-Pot Synthesis of Metastable 2,5-Dihydrooxepines through Retro-Claisen Rearrangements: Method and Applications |
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Authors: | Dr. Wei Zhang Dr. Emmanuel Baudouin Marie Cordier Dr. Gilles Frison Dr. Bastien Nay |
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Affiliation: | 1. Laboratoire de Synthèse Organique, Ecole Polytechnique, CNRS, ENSTA, Institut Polytechnique de Paris, 91128 Palaiseau, France;2. Laboratoire de Biologie du Développement, Institut de Biologie Paris Seine, Sorbonne Université, CNRS, Paris, 75005 France;3. Laboratoire de Chimie Moléculaire, Ecole polytechnique, CNRS, Institut Polytechnique de Paris, 91128 Palaiseau, France |
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Abstract: | A one-pot methodology to synthesize metastable bicyclic 2,5-dihydrooxepines from cyclic 1,3-diketones and 1,4-dibromo-2-butenes through the retro-Claisen rearrangement of syn-2-vinylcyclopropyl diketone intermediates is reported. DFT calculations were performed to understand the reaction selectivity and mechanisms towards [1,3]- or [3,3]-sigmatropic rearrangements, highlighting the crucial influence of the temperature. The reaction was successfully applied to a short protecting group-free total synthesis of radulanin A, a natural 2,5-dihydrobenzoxepine. Moreover, the strong herbicidal potential of this natural product is demonstrated for the first time. |
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Keywords: | 2,5-dihydrooxepines density functional calculations herbicides sigmatropic rearrangement total synthesis |
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