22445-58-5Relevant academic research and scientific papers
Ring-opening metathesis polymerization with the second generation hoveyda-grubbs catalyst: An efficient approach toward high-purity functionalized macrocyclic oligo(cyclooctene)s
Blencowe, Anton,Qiao, Greg G.
, p. 5717 - 5725 (2013/05/21)
Herein, we present a facile and general strategy to prepare functionalized macrocyclic oligo(cyclooctene)s (cOCOEs) in high purity and high yield by exploiting the ring-opening metathesis polymerization (ROMP) intramolecular backbiting process with the commercially available second generation Hoveyda-Grubbs (HG2) catalyst. In the first instance, ROMP of 5-acetyloxycyclooct-1-ene (ACOE) followed by efficient quenching and removal of the catalyst using an isocyanide derivative afforded macrocyclic oligo(5-acetyloxycyclooct-1-ene) (cOACOE) in high yield (95%), with a weight-average molecular weight (Mw) of 1.6 kDa and polydispersity index (PDI) of 1.6, as determined by gel permeation chromatography (GPC). The structure and purity of the macrocycles were confirmed by NMR spectroscopy and elemental analysis, which indicated the complete absence of end-groups. This was further supported by GPC-matrix assisted laser desorption ionization time-of-flight mass spectroscopy (GPC-MALDI ToF MS), which revealed the exclusive formation of macrocyclic derivatives composed of up to 45 repeat units. Complete removal of residual ruthenium from the macrocycles was confirmed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The same methodology was subsequently extended to the ROMP of 5-bromocyclooct-1-ene and 1,5-cyclooctadiene to prepare their macrocyclic derivatives, which were further derivatized to produce a library of functionalized macrocyclic oligo(cyclooctene)s. A comparative study using the second and third generation Grubbs catalysts in place of the HG2 catalyst for the polymerization of ACOE provided macrocycles contaminated with linear species, thus indicating that the bidendate benzylidene ligand of the Hoveyda-Grubbs catalyst plays an important role in the observed product distributions.
Gels based on cyclic polymers
Zhang, Ke,Lackey, Melissa A.,Cui, Jun,Tew, Gregory N.
, p. 4140 - 4148 (2011/05/07)
Cyclic poly(5-hydroxy-1-cyclooctene) (PACOE) was synthesized by ring-expansion metathesis polymerization (REMP), and thiol-ene chemistry was used to cross-link the internal double bonds in the PACOE backbone. This created a novel network material (gels formed from cyclic polymers) with unique structural units, where the cyclic PACOE main chains, which serve as secondary topological cross-linkages, were connected by primary intermolecular chemical cross-linkages. The resulting properties were notably different from those of traditional chemically cross-linked linear PACOE gels, whose gel fraction (GF) and modulus (G) increased while the swelling ratio (Q) decreased with increasing initial polymer concentration in the gel precursor solution (C0). For the gels formed from cyclic polymers, however, the GF, Q, and G all simultaneously increased as C0 increased at the higher range. Furthermore, at the same preparation state (same C0), the swelling ability and the maximum strain at break of the gels formed from cyclic polymers were always greater than those of the gels formed from linear polymers, and these differences became more pronounced as C0 increased.
Hydroacetoxylation of olefins with acetic acid genetated in situ from vinyl acetate in the presence of ruthenium complexes
Khusnutdinov,Shchadneva,Khisamova,Dzhemilev
experimental part, p. 155 - 160 (2011/05/03)
Ruthenium complexes catalyze the decomposition of vinyl acetate releasing the acetic acid and its subsequent addition to linear and cyclic olefins.
Oxymetallation. Part 13. Synthesis of Bicyclic Peroxides via Peroxymercuriation of Cyclic Dienes
Bloodworth, A.J.,Khan, Jamil A.,Loveitt, M.E.
, p. 621 - 632 (2007/10/02)
The bis-mercuriated derivative (12) of 9,10-dioxabicyclodecane has been prepared by peroxymercuriation of cis,cis-octa-1,5-diene, but substantial amounts of bicyclic ethers are also formed in the reaction.The bicyclic peroxides (4) and (5) have been obtained from (12) by reduction and brominolysis respectively. 8,9-Dioxabicyclodecane (6) and the dibromo-derivative (7) have similarly been prepared by peroxymercuriation and demercuriation of cyclo-octa-1,4-diene.It is suggested that the isomeric purity of the peroxides and the concurrent formation of bicyclic ethers both result from equilibrium control of reversible (per)oxymercuriation-de(per)oxymercuriation.A low yield of the -peroxide (8) has been obtained by peroxymercuriation and brominolysis of cyclohexa-1,4-diene, but attempts to prepare -compounds from 5,5-disubstituted cyclopentadienes have been unsuccessful.
