Functionalized cross-linked poly(vinyl alcohol) resins as reaction scavengers and as supports for solid-phase organic synthesis

New hydrophilic poly(vinyl alcohol) (PVA-OH) resins were prepared by an inverse suspension polymerization using epichlorohydrin as a cross-linker. These novel resins swell in a variety of solvents commonly used in solid-phase organic synthesis, such as dicholomethane, dioxane, methanol, tetrahydrofuran, and dimethyl-formamide. In addition, PVA-OH shows excellent swelling in water. The cross-linked PVA-OH beads were functionalized with an aldehyde group and were tested as scavengers for primary amines in three different reactions: amide bond formation, reductive amination reaction, and urea formation. With 1-2 equiv of the PVA aldehyde resin, all the excess primary amines were successfully scavenged. The utility of PVA-OH resins as solid supports in mono- and dipeptide synthesis was also investigated using symmetrical anhydride and MSNT/MeIm (2,4,6-mesitylenesulfonyl-3-nitro-1,2,4-triazolide in the presence of 1-methylimidazol) methods.