End-labeled amino terminated monotelechelic glycopolymers generated by ROMP and Cu(I)-catalyzed azide–alkyne cycloaddition

• Ronald Okoth and
• Amit Basu

Beilstein J. Org. Chem. 2013, 9, 608–612, doi:10.3762/bjoc.9.66

• metathesis; triazole; Findings Polymers functionalized with carbohydrate side chains, also referred to as glycopolymers, constitute important synthetic probes for the study of carbohydrate recognition [1][2][3]. Glycopolymers prepared by ring-opening metathesis polymerization (ROMP) of norbornene and

• cyclooctenes have been used to examine the role of glycans in such processes such as neurite outgrowth [4], bacterial motility [5], and inflammation [6]. ROMP polymers with pendant reactive functional groups, such as N-hydroxysuccinimide (NHS) or nitrophenyl esters, are useful materials since the pendant

• reaction as well as subsequent polymer modifications, and that can also be removed under mild conditions for the subsequent functionalization of an amine-terminated polymer. We report here the development of the terminating agent 3, which caps a ROMP-derived polymer with a 2-trimethylsilylethyl carbamate

Olefin metathesis in nano-sized systems

• Didier Astruc,
• Abdou K. Diallo,
• Sylvain Gatard,
• Liyuan Liang,
• Cátia Ornelas,
• Victor Martinez,
• Denise Méry and
• Jaime Ruiz

Beilstein J. Org. Chem. 2011, 7, 94–103, doi:10.3762/bjoc.7.13

• olefin metathesis and dendrimers and other nano systems is addressed in this mini review mostly based on the authors’ own contributions over the last decade. Two subjects are presented and discussed: (i) The catalysis of olefin metathesis by dendritic nano-catalysts via either covalent attachment (ROMP

• ][25]. The three first generations of metallodendrimers 2 and the model complex do not catalyze RCM reactions, but they were efficient catalysts for the ROMP of norbornene under ambient conditions, giving dendrimer-cored stars (Scheme 1 and Scheme 2) [24][25]. Analysis of the molecular weights by size

• , and these were slightly more reactive ROMP catalysts for the polymerization of norbornene than those carrying cyclohexyl substituents [25]. These new dendritic ligands, in particular those of low generation (with up to 8 branches), also proved very efficient in palladium catalysis [26][27][28][29][30

Hoveyda–Grubbs type metathesis catalyst immobilized on mesoporous molecular sieves MCM-41 and SBA-15

• Hynek Balcar,
• Tushar Shinde,
• Naděžda Žilková and
• Zdeněk Bastl

Beilstein J. Org. Chem. 2011, 7, 22–28, doi:10.3762/bjoc.7.4

• metathesis polymerization (ROMP) of cyclooctene, ring-closing metathesis (RCM) of diallylsilanes and several types of cross-metathesis reactions. High stability of catalysts, reusability and low Ru leaching were also reported. However, the mode of attachment of the Ru species on the silica surface was

• , respectively. The catalytic activity was tested in the RCM of 1,7-octadiene (Scheme 1, entry 1) and diethyl diallylmalonate (DEDAM) (Scheme 1, entry 2), in the metathesis of methyl oleate (Scheme 1, entry 3) and methyl 10-undecenoate (Scheme 1, entry 4), and in the ROMP of cyclooctene (Scheme 1, entry 5

• reactions with 3/MCM-41 and 3/SBA-15. Selectivity near 100% was achieved in all cases. The ROMP reactions were carried out for cyclooctene with both 3/MCM-41 and 3/SBA-15 (cyclooctene/Ru molar ratio = 500, c0cyclooctene = 0.6 mol/L, T = 30 °C). High molecular weight polymers (Mw = 250 000, Mn = 110 000

ROMP-Derived cyclooctene-based monolithic polymeric materials reinforced with inorganic nanoparticles for applications in tissue engineering

• Franziska Weichelt,
• Solvig Lenz,
• Stefanie Tiede,
• Ingrid Reinhardt,
• Bernhard Frerich and
• Michael R. Buchmeiser

Beilstein J. Org. Chem. 2010, 6, 1199–1205, doi:10.3762/bjoc.6.137

• -opening metathesis polymerization (ROMP); tissue engineering; Introduction Tissue engineering (TE), a sub-area of regenerative medicine, brings together diverse technologies and interdisciplinary fields such as biology, engineering, material and life sciences, polymer and inorganic chemistry [1][2][3

• metathesis polymerization (ROMP) derived norborn-2-ene (NBE)-based monolithic materials have previously been successfully tested for both osseous and adipose cell growth [6]. However, it has also been reported that the mechanical properties, such as hardness, of such scaffold materials were quite low. Harder

• osteoinductive and provide mechanical support when needed [15]. As an alternative to poly(NBE)-based monoliths, we investigated the preparation of monolithic structures from a highly polar cyclooctene derivative. So far, ROMP-derived monolithic materials have successfully been applied to separation science as

The catalytic performance of Ru–NHC alkylidene complexes: PCy₃ versus pyridine as the dissociating ligand

• Stefan Krehl,
• Diana Geißler,
• Sylvia Hauke,
• Oliver Kunz,
• Lucia Staude and
• Bernd Schmidt

Beilstein J. Org. Chem. 2010, 6, 1188–1198, doi:10.3762/bjoc.6.136

• catalyst is available from the M2 complex by ligand substitution [18] and shows high activity in living ROMP [40], whereas the reactivity in some RCM and CM reactions appears to be diminished [18][41]. During our research directed at the development of novel metathesis-non metathesis reaction sequences [42

About the activity and selectivity of less well-known metathesis catalysts during ADMET polymerizations

• Hatice Mutlu,
• Lucas Montero de Espinosa,
• Oĝuz Türünç and
• Michael A. R. Meier

Beilstein J. Org. Chem. 2010, 6, 1149–1158, doi:10.3762/bjoc.6.131

• catalytic activities in RCM of linear dienes [32][34][35] and ROMP of cycloolefins [36][37][38][39][40] were reported. RCM studies with diethyl diallylmalonate and diallyl tosylamine as substrates showed an appreciable catalytic activity and selectivity for the 2nd generation 16-electron Ru–indenylidene

• ]. Research performed by Monsaert et al. illustrated that C2 enables high conversions in ROMP of 1,5-cyclooctadiene, and conversions of up to 80% in the RCM of diethyl diallylmalonate in short reaction times (5–10 min), thus being superior to the benzylidene analogue [35]. Recently, a useful and practical

Miniemulsion polymerization as a versatile tool for the synthesis of functionalized polymers

• Daniel Crespy and
• Katharina Landfester

Beilstein J. Org. Chem. 2010, 6, 1132–1148, doi:10.3762/bjoc.6.130

• copolymerization of isoprene afforded low crystalline polymers. After Grubbs popularized water resistant catalysts for metathesis polymerizations, it became clear that metathesis could be also performed in aqueous heterophase systems. Claverie et al. studied the ring-opening metathesis polymerization (ROMP) in

• . Another group compared the dispersion, miniemulsion, and suspension polymerization for the ROMP of norbornene or cyclooctadiene [70]. For the miniemulsions, two approaches were followed, i.e., the addition of a catalyst solution to a miniemulsion of the monomer and the addition of monomer to miniemulsion

• prepared as shown in Scheme 1 and used in the direct miniemulsion ROMP of norbornene [71]. Particles with sizes of 200–250 nm could be obtained. The catalytic polymerization of norbornene in direct miniemulsion was also carried out in the presence of an oil-soluble catalyst that was generated in situ, or

Light-induced olefin metathesis

• Yuval Vidavsky and
• N. Gabriel Lemcoff

Beilstein J. Org. Chem. 2010, 6, 1106–1119, doi:10.3762/bjoc.6.127

• present developments in the use of light to expedite olefin ring-closing, ring-opening polymerisation and cross-metathesis reactions. Keywords: catalysis; light activation; olefin metathesis; photoactivation; photoinitiation; photoisomerisation; RCM; ROMP; ruthenium; tungsten; Introduction The metal

• -defined early transition metal complexes for photocatalysed ROMP (PROMP) 3 and 4 (Figure 1) was published by van der Schaaf, Hafner, and Mühlebach [59]. Complexes 3 and 4 displayed reasonable thermal stability in solution (no decomposition was observed after 1 d at 80 °C), but were moisture sensitive and

• systems showed none to moderate activity for normal ROMP, and were not sensitive to oxygen and humidity compared to the tungsten initiators described above. Notably, heating the sandwich catalysts for more than 24 h at 50 °C in the presence of the monomers did not induce polymerisation, on the other hand

Halide exchanged Hoveyda-type complexes in olefin metathesis

• Julia Wappel,
• César A. Urbina-Blanco,
• Mudassar Abbas,
• Jörg H. Albering,
• Robert Saf,
• Steven P. Nolan and
• Christian Slugovc

Beilstein J. Org. Chem. 2010, 6, 1091–1098, doi:10.3762/bjoc.6.125

• catalytic performance of the complexes in ring opening metathesis polymerisation, ring closing metathesis, enyne cycloisomerisation and cross metathesis reactions. Keywords: cross metathesis; olefin metathesis; RCM; ROMP; ruthenium; Introduction Since the pioneering reports on the utilisation of N

• these compounds in ring opening metathesis polymerisation (ROMP) [21] was also studied. Results and Discussion Synthesis and characterisation Although complex 1 is commercially available, we prepared 1 from (H2IMes)(PCy3)Cl2Ru(3-phenyl-indenylid-1-ene) (M2) as the ruthenium-containing starting material

• contact with other ligands – which would distort the complex severely – by shifting their positions towards (chloride) or away from (iodide) the empty coordination position, depending on the Ru–X distances. Catalytic testing of the compounds ROMP Initiators 1–3 were benchmarked in the ROMP of dimethyl

Synthesis and crossover reaction of TEMPO containing block copolymer via ROMP

• Olubummo Adekunle,
• Susanne Tanner and
• Wolfgang H. Binder

Beilstein J. Org. Chem. 2010, 6, No. 59, doi:10.3762/bjoc.6.59

•  = tricyclohexylphosphine), [(H2IMes)(PCy3)Cl2Ru(3-phenylinden-1-ylidene)] U2 (H2IMes = 1,3-bis(mesityl)-2-imidazolidinylidene), [(H2IMes)(py)Cl2Ru(3-phenylinden-1-ylidene)] U3 (py = pyridine or 3-bromopyridine) via ring opening polymerization (ROMP). The crossover reaction and the polymerization kinetics were investigated

• polymerization in comparison to U1. The synthesis of block copolymers with molecular weights up to Mn = 31 000 g/mol with low polydispersities (Mw/Mn = 1.2) is reported. Keywords: block copolymer (BCP); crossover reaction; MALDI; NEOLYST™; ROMP; Introduction Block copolymers are macromolecules composed of

• achieved extensively via living polymerization methods. Thus, besides acyclic diene metathesis polymerization (ADMET) [2], ring opening metathesis polymerization (ROMP) [3][4][5] is another type of olefin metathesis polymerization that can be used for the synthesis of block copolymers. Early examples of

Ring opening metathesis polymerization-derived block copolymers bearing chelating ligands: synthesis, metal immobilization and use in hydroformylation under micellar conditions

• Gajanan M. Pawar,
• Jochen Weckesser,
• Siegfried Blechert and
• Michael R. Buchmeiser

Beilstein J. Org. Chem. 2010, 6, No. 28, doi:10.3762/bjoc.6.28

• N,N-dipyrid-2-ylacetamide and their use in hydroformylation reactions [9]. Here, we report on the immobilization of a Rh-N,N-dipyrid-2-ylacetamide-based catalyst on a soluble, amphiphilic, ring-opening metathesis polymerization- (ROMP) derived block copolymer and its use in hydroformylation [10

• was converted into M2 via quaternization of the tertiary amine with methyl iodide. Synthesis of homo- and block copolymers via ROMP [12][13] ROMP has already been used for the synthesis of micelle-forming block copolymers [14], however, the one used in this study, i.e. poly(M1-b-M2), required special

• bearing a chelating N,N-dipyrid-2-ylamide-based ligand was prepared via ROMP using a Mo-based Schrock initiator. Loading with Rh(I) yielded a polymer-bound catalyst that was used for the hydroformylation of 1-octene. From the hydroformylation data obtained with the polymer-bound catalyst as well as with