The ability to handle gaseous reagents presents a number of challenges for synthetic chemists. The problem becomes particularly acute when scaling up biphasic (liquid/gas) or even triphasic (gas/liquid/solid) systems due to limiting mass transfer effects. Pressure vessels or autoclaves are also not always practical and easy to come by. A practical solution to this (if

Figure 1 I guess to qualify as a reagent of the month the material has to fulfil certain criteria and commercial availability, though not essential, is very desirable. N-((Methylsulfonyl)oxy)acetimiodyl chloride (henceforth known, at least by me, as Fier’s reagent) is now available to buy from Sigma Aldrich (CAS: 1433887-06-9). The compound is an air and