Taming tosyl azide: the development of a scalable continuous diazo transfer process
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Deadman, Benjamin J.
O'Mahony, Rosella M.
Crowley, Daniel C.
Collins, Stuart G.
Maguire, Anita R.
Royal Society of Chemistry
Heat and shock sensitive tosyl azide was generated and used on demand in a telescoped diazo transfer process. Small quantities of tosyl azide were accessed in a 'one pot' batch procedure using shelf stable, readily available reagents. For large scale diazo transfer reactions tosyl azide was generated and used in a telescoped flow process, to mitigate the risks associated with handling potentially explosive reagents on scale. The in situ formed tosyl azide was used to rapidly perform diazo transfer to a range of acceptors, including beta-ketoesters, beta-ketoamides, malonate esters and beta-ketosulfones. An effective in-line quench of sulfonyl azides was also developed, whereby a sacrificial acceptor molecule ensured complete consumption of any residual hazardous diazo transfer reagent. The telescoped diazo transfer process with in-line quenching was used to safely prepare over 21 g of an alpha-diazocarbonyl in > 98% purity without any column chromatography.
Continuous flow synthesis , C-H insertion , Alpha-diazocarbonyl compounds , Hetero-Wolff rearrangement , Beta-oxo sulfoxides , Organic synthesis , Carbene insertion
Deadman, B. J., O'Mahony, R. M., Lynch, D., Crowley, D. C., Collins, S. G. and Maguire, A. R. (2016) 'Taming tosyl azide: the development of a scalable continuous diazo transfer process', Organic & Biomolecular Chemistry, 14(13), pp. 3423-3431. doi: 10.1039/c6ob00246c
© The Royal Society of Chemistry 2016