Pyridinium methylides cycloaddition with

Pyridinium methylides. Trimethylsilylmethyl triflate converts pyridines into N-(trimethylsilylmethyl)pyridinium triflates in high yield. On treatment with cesium fluoride these products are converted into nonstabilizcd pyridinium methylides. which can be trapped by cycloaddition to dimethyl acetylenedicarboxylate to form indolizincs. [Pg.542]

A pyridinium methylide can undergo a novel reaction with an electron-deficient alkene to provide the next higher homolog in which the original double bond is saturated and a methylene group is added. This reaction fails with hindered alkenes, and apparently requires DME as solvent. A [3 + 2] cycloaddition may be the initial step. [Pg.543]

Charge-transfer complexes with pyridinium cations 82UK185. Cycloaddition reactions of pyridinium N-methylides 82WCH231. Nucleophilic reactions of pyridinium salts 83MI13. [Pg.325]

Matsumoto K, IkemiY, KonishiH, ShiX-L, UchidaT(1988) Site selectivity in the 1,3-dipolar cycloaddition reaction of unsymmetric pyridinium bis(methoxycarbonyl)methylides with methyl propiolate. Heterocycles 11 2557-2562... [Pg.179]

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