“…[5][6][7] Nevertheless, their application was limited to homogeneous catalysis in organic solvents for more than a decade. Since then, reports about their linkage to water-soluble polymers [8,9] or silica-based surfaces, [9] their introduction into carbohydrates, [10] and their functionalization with hydrophilic groups, such as carboxylate [11,12] or sulfonate, [12] have been reported. [13] The objective of these latter studies was an improved water solubility which would lead to an easier separation of product and catalyst, and ultimately even the opportunity of catalyst recycling.…”