- Exploring the Reactivity of α-Lithiated Aryl Benzyl Ethers: Inhibition of the [1,2]-Wittig Rearrangement and the Mechanistic Proposal Revisited
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By carefully controlling the reaction temperature, treatment of aryl benzyl ethers with tBuLi selectively leads to α-lithiation, generating stable organolithiums that can be directly trapped with a variety of selected electrophiles, before they can undergo the expected [1,2]-Wittig rearrangement. This rearrangement has been deeply studied, both experimentally and computationally, with aryl α-lithiated benzyl ethers bearing different substituents at the aryl ring. The obtained results support the competence of a concerted anionic intramolecular addition/elimination sequence and a radical dissociation/recombination sequence for explaining the tendency of migration for aryl groups. The more favored rearrangements are found for substrates with electron-poor aryl groups that favor the anionic pathway.
- Velasco, Rocío,Silva López, Carlos,Nieto Faza, Olalla,Sanz, Roberto
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supporting information
p. 15058 - 15068
(2016/10/11)
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- Syntheses and anti-inflammatory activity of natural 1,3-diarylpropenes
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First syntheses of five natural 1,3-diarylpropenes (cinnamylphenols) 2-4, 7, and 8 along with synthesis of two other natural 1,3-diarylpropenes 1 and 5 and E-isomer of mucronulastyrene (6) were achieved by Friedel- Crafts alkylation as a key step. Subsequ
- Jung, Jong-Woon,Kim, Jin-Kyung,Jun, Jong-Gab
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p. 632 - 637
(2016/06/09)
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- Chinone von Benzo- und Dibenzokronenethern
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The preparation of the 1,4-quinones of benzocrown-5 (1), benzocrown-6 (2), and dibenzocrown-6 (3) and their quinols is described.The quinones are obtained by Fremy salt oxidation of the corresponding 3-hydroxybenzo-crown ethers which are readily accessible by a double protective group synthesis from 1,2,3-trihydroxybenzene.The synthetic pathway also provides a general high yield preparation of 2,3-dialkoxy-1,4-benzoquinones.The new crown ethers are characterised by 1H- and 13C-N.M.R. as well as U.V. spectroscopy.Non-aqueous redox potentials aredetermined by cyclic voltammetry.Crystalline complexes of 1 and 2 with various ammonium, alkali, and alkaline earth cations are also described.
- Dietl, F.,Gierer, G.,Merz, A.
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p. 626 - 631
(2007/10/02)
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