“…Therefore, they are ideal gas-loading systems, capable of introducing a gaseous reagent to the MW vessel at a variety of pressures [37]. Hydrogen gas has been the most widely used gaseous reagent in MW-assisted reactions, examples including hydrogenation of olefins [38,39], hydrodechlorination [40,41], debenzylation [42,43], reductive aminations [44], azide reductions [43], and dearomitization of pyridine derivatives to form saturated piperidines [43]. Molecular oxygen [45,46], 1-propyne [47], and ethene [48,49] have also seen use as reagents in reactions using MW heating.…”