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Primary vinylarenes are regarded as important monomers for the production of materials, including ion exchange membranes for electrolyzers. Due to the high cost of certain vinylarenes and the relative affordability of their aldehyde precursors, their synthesis was explored using flow chemistry to enable safe and scalable production. Limited success was achieved with a soluble methanolic Wittig reaction, while an alternative approach based on Peterson olefination was found to be high-yielding. In this method, a (trimethylsilyl)methyl Grignard reagent was generated in flow using a magnesium-filled column. Using this approach, 2-vinylthiophene was obtained in 93% yield on a 37 g scale, and the method was successfully applied to other nonpolar arenes. In the case of polar arenes, precipitation at the oxymagnesium chloride stage and inefficient elimination were encountered; however, these challenges were mitigated by the use of a (phenyldimethylsilyl)methyl Grignard reagent and the application of a stronger acid at elevated temperature for the elimination step.
- Burrell, MJ
- Varcoe, JR
- Whelligan, DK
- School of Chemistry and Chemical Engineering, University of Surrey, Guildford GU2 7XH, U. K
