Synthesis of Polyspiroketals Containing Five-, Six-, Seven-, and Eight-Membered Rings

Abstract

Since the study of model compounds had shown that ketals containing five-, six-, seven-, and eight-membered rings could be formed in very high yields by heating a ketone or diketone with a diol in the presence of an acid catalyst with removal of the water that was formed by azeotropic distillation, these reactions were extended to produce a series of new analogous polyspiroketals. Furthermore since the formation of the intermediate hemiketal is not a stable product and it is necessary to proceed all the way to the ketal before a stable unit is formed, this reaction appeared ideal for the synthesis of soluble linear polyspiroketals containing only cyclicized structures. This reaction also represents a condensation polymerization analog of the free radical inter-intramolecular polymerization to produce linear polymers. Thus it was shown that linear soluble polymers could be prepared from the following polyfunctional materials: a five-membered ring -containing polyketal from 1,2,4,5-tetrahydroxy-cyclohexane and 1,4-cyclohexanedione; six-membered ring-containing polyketal from 1,1,4,4-tetrakis(hydroxymethyl)cyclohexane, and 1,1,6,6-tetrakis(hydroxymethyl) cyclohexanone; six-membered ring-containing polyketal from 1,3-dihydroxyacetone, as well as 1,10-cyclooctadecanedione and pentaerythritol; a seven-membered ring -containing polyketal from 1,4-cyclohexanedione and 1,2,4,5-tetrakis(hydroxymethy1)-

Efficient synthesis of 2-methylene-4-phenyl-1,3-dioxolane, a cyclic ketene acetal for controlling the NMP of methyl methacrylate and conferring tunable degradability

“…Cyclic ketene acetals (CKA) are undoubtedly the most extensively studied family of monomers for rROP. 2 They were the subject of extensive research by Bailey and co-workers in the early 1980s [5][6][7][8][9][10][11][12] and have attracted renewed attention over the last decade as comonomers to confer degradability to vinyl polymers, via conventional radical polymerization [13][14][15][16][17][18][19][20] and reversible deactivation radical polymerization (RDRP) techniques. [21][22][23][24][25][26][27][28][29] This was illustrated by the synthesis of a variety of degradable copolymers designed for biomedical applications including biomaterials, drug delivery and tissue engineering.…”

Terephthalaldehyde- and isophthalaldehyde-based polyspiroacetals

“…A number of other polyspiroketals were also prepared by the condensations of various cyclic diketones and tetraols, resulting in polymers with good chemical and thermal stabilities. 5 Several spiroacetals were prepared by the reaction of carbonyl compounds and multihydroxy monomers. Cohen and coworkers synthesized thermoplastic polyspiroacetal resins using dialdehydes with pentaerythritol or pentaerythritol-dipentaerythritol mixtures.…”

100th Anniversary of Macromolecular Science Viewpoint: Degradable Polymers from Radical Ring-Opening Polymerization: Latest Advances, New Directions, and Ongoing Challenges

“…Even though rROP was been discovered in the 1980s, − there has been a recent resurgence of interest in this technique, especially since the advent of reversible deactivation radical polymerization (RDRP). − Contrary to free-radical polymerization (FRP), RDRP indeed allows the preparation of well-defined, functional, and complex macromolecular architectures and has been the focus of considerable attention. Therefore, combining RDRP and rROP has opened new avenues not achievable with traditional polyesters, toward advanced, degradable polymeric materials, by a simple, yet efficient, radical polymerization process.…”