Preparation of New Microgel Polymers and Their Application as Supports in Organic Synthesis

Abstract

A series of soluble microgel polymers have been synthesized using solution-phase polymerization reactions. In a systematic manner, several variables such as monomer concentration, cross-linker content, reaction solvent and reaction time were examined, and this provided an optimal polymer with both solubility and precipitation characteristics suitable for synthetic applications. Thus, a chemically functionalized microgel polymer was synthesized, and the utility of this polymer in the synthesis of a small array of oxazole compounds has been demonstrated. The advantage of the microgel polymers produced was that they exhibited solution viscosities lower than those of conventional linear polymers even at higher concentrations, and this was found to be beneficial for their precipitation properties. Compounds prepared using the described microgel polymer supports were obtained in similar yields and purity when compared with insoluble resins, and more importantly, the soluble polymer bound intermediates could be analyzed at each step using standard NMR techniques.

A Polymer‐Supported Chiral Dirhodium(II) Complex: Highly Durable and Recyclable Catalyst for Asymmetric Intramolecular CH Insertion Reactions

“…Although it is documented that low reaction temperatures (−78 °C) are key to the suppression of β‐hydride elimination,15g, 16, 28 there is no immobilized dirhodium(II) catalyst available for carbene transformations below room temperature. The reaction of 11 with 2 mol % of the immobilized catalyst 5 proceeded at −78 °C to provide methyl cis ‐2‐phenylcyclopentane‐1‐carboxylate ( 12 ) as the sole product in 94 % ee , and there was no trans isomer 13 or alkene product 14 , even though catalyst 5 displayed low reactivity relative to 3 (Table 1, entry 1 versus 2) 29. This result indicates that the present method of immobilization using monomer 4 produced very little effect on the chiral environment around the immobilized catalyst.…”

Synthesis and Applications of Nano Metallic Particles Anchored on a Novel Polymeric Resin

“…In addition to PS-DVB resin a number of polymers are used in the development of polymer 14,15 , Janda gel 16 , Tenta gel 17 and polyacrylamides 18 . Various organic polymer supports used were extensively reviewed 19,20 .…”

Polymer Microgels for Catalysis

“…It is important for the morphology control to select suitable poor solvents and the volume ratio of monomer and solvents (37). Homogeneous systems are applicable to various monomers, such as methacrylate, styrene, and acrylamide, to give fully soluble microgels with relatively small size (<100 nm) (38). The diluted condition is critical to prevent macroscopic gelation.…”