5345-42-6Relevant articles and documents
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Barger,Schlittler
, p. 381,389 (1932)
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The mechanism of the ortho-methylation of nitrobenzenes by dimethylsulfonium methylide
Haiss, Peter,Zeller, Klaus-Peter
experimental part, p. 295 - 301 (2011/02/28)
Nitrobenzenes carrying an ortho substituent are selectively methylated at the free ortho position by reaction with dimethylsulfonium methylide. The importance of the ortho substituent is demonstrated by the failure of the methylation of nitrobenzene and 3- and 4-nitroanisole. This is explained by the out-of-plane geometry of the nitro group in the ortho-substituted derivative, which enables a specific interaction between the ylide and the nitro group favourable for attack of the methylide C atom at the neighbouring free ortho position. As shown by appropriate deuterium-labelling studies, the addition is followed by an E1-like β-elimination with displacement of dimethyl sulfide and subsequent protonation of the elimination product. The nucleophilic ortho-methylation of 2-nitroanisole by dimethylsulfonium methylide is explained by a reaction sequence including intermediates A to D. Copyright
Expeditious synthesis of benzopyrans via lewis acid-catalyzed C-H functionalization: Remarkable enhancement of reactivity by an ortho substituent
Mori, Keiji,Kawasaki, Taro,Sueoka, Shosaku,Akiyama, Takahiko
supporting information; experimental part, p. 1732 - 1735 (2010/09/05)
An expeditious construction of a benzopyran skeleton via Lewis acid-catalyzed C-H functionalization was achieved. In this process, a [1,5] hydride shift and 6-endo cyclization successively occurred to give benzopyrans. The presence of substituents ortho to the alkoxy group significantly enhanced the reactivity, affording the desired compounds in excellent chemical yields with short reaction times.
