paraffin capsules in which they mechanically removed the core, loaded the capsule with air-and moisture-sensitive palladium (pre-)catalysts and metal salts and then sealed them again. The capsules could then be removed from the glove box, safely handled in ambient conditions, and subsequently used to dose the reagents into a range of cross-coupling reactions (Figure ). Other researchers have applied this general approach to a variety of reactions including potassium hydride. Paraffin reagent capsules have also been reported to have the benefit of protecting other species in multi-step reactions from processes such as catalyst poisoning and undesired side reactions, making product purification easier. In related work, but with a focus on toxic and malodorous reagents, Richert and co-workers reported a crystalline coating for reagents based on tetrakis(dimethoxyphenyl)adamantane. Xu and co-workers used a tableting approach based on mixing poly(tetrafluoroethylene) and cross-linked poly(styrene) with solid reagents, and then coating them with the same polymer mix to enhance stability. Braje, Jolit and co-workers very recently made use of hydroxypropyl methylcellulose capsules of the type used for drug delivery to stabilise and simultaneously deliver catalyst, ligand and base into cross-coupling reactions. With specific regard to organolithium reagents, the Hevia group has reported that deep eutectic solvents (DESs) can be used for the delivery of organolitihums into a range of reactions, and play a role in minimising hydrolysis and other side reactions (Figure ). Capriati and co-workers have performed Pd-catalysed crosscoupling reactions using organolithiums in aqueous conditions, albeit the reactions were very fast (<1 min reaction times). Figure . Schematic of selected relevant technologies for delivery of reactive species, including paraffin capsules (Buchwald and co-workers ) and ionic liquids (Hevia and co-workers ).