Simple tool for adding solid catalysts without contamination by oxygen or moisture

Abstract Even though catalyst loading is one of the first crucial steps in organic and inorganic catalytic reactions, it has not been frequently discussed or improved to date. In particular, when a solid catalyst is added to an oxygen- and moisture-sensitive reaction mixture, a carefully tuned process to ensure an inert atmosphere (under nitrogen or argon) is required. Although gloveboxes are nowadays considered to be a universal solution, it is still associated with unsolved problems, such as high cost, high space consumption, difficult temperature control, and handling difficulties on account of the gloves. Herein, we report a recently developed simple apparatus that enables the addition of a solid without opening the reaction vessel. This solid-addition funnel drastically improved the yield (from trace to 64%) and the reproducibility of our original glycosylation reaction.