- Intermediate in Sommelet-Hauser Rearrangement of N,N-Dimethylbenzylammonium N-Methylides
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Formation of benzylammonium N-methylides by fluoride anion induced desilylation of dimethyl(4-substituted benzyl)ammonium halides (1) and 3-substituted benzyl analogues (6) was examined to isolate 5--6-methylene-1,3-cyclohexadienes (isotoluene intermediates, 3,8,10) in the Sommelet-Hauser rearrangement.Some isotoluenes were isolated and their structures were confirmed by 1H NMR analysis.The stability of the isotoluenes was dependent on the electron-donating effects of the substituents on the conjugated bonds, and 3-methoxy-substituted isotoluene 3a was the most stable compound studied.
- Shirai, Naohiro,Watanabe, Yoko,Sato, Yoshiro
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p. 2767 - 2770
(2007/10/02)
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- Rearrangement of (Substituted benzyl)trimethylammonium Ylides in a Nonbasic Medium: The Improved Sommelet-Hauser Rearrangement
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Benzyl quaternary ammonium ylide formation in a nonbasic medium was accomplished by fluoride anion induced desilylation of benzyldimethylammonium bromide (3a) and ortho- or para-substituted benzyl analogues 3b-k.Treatment of 3 with CsF in HMPA at room temperature gives high yields of the Sommelet-Hauser rearrangement products 7 from 3a and methyl-, acetoxy-, and chloro-substituted analogues 3b-f.However, formation of the Stevens rearrangement products 8 is competitive for the reaction of compounds 3g-k having strong electron-withdrawing substituents such as acetyl, cyano, and nitrogen groups.From the o-cyano-substituted analogue 3h, a considerable amount of para Sommelet-Hauser rearrangement product is isolated.
- Nakano, Mitsuji,Sato, Yoshiro
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p. 1844 - 1847
(2007/10/02)
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- A Convenient Synthesis of o-Methylbenzylamine Derivatives from Benzyl Halides: The Improved Sommelet-Hauser Rearrangement
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Desilylation by fluoride anion of benzyldimethyl(trimethylsislylmethyl)ammonium halides having a Cl(1-), CN(1-), or AcO(1-) substituent on the benzene ring gave high yields of the Sommelet-Hauser rearrangement products at room temperature.
- Nakano, Mitsuji,Sato, Yoshiro
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p. 1684 - 1685
(2007/10/02)
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