Substituent Effects Provide Access to Tetrasubstituted Ring-Opening Olefin Metathesis of Bicyclo[4.2.0]oct-6-enes

Youn, Gyusaang; Sampson, Nicole S.

doi:10.1021/acsorginorgau.1c00016

Cited by 4 publications

(5 citation statements)

References 35 publications

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“…The ruthenium-catalyzed AROMP of low-strain cyclic olefins and bicylo[4.2.0]octenes has been investigated extensively and has been championed for producing copolymers that can display a variety of functional groups, controlled backbone sequences, and tunable material properties such as hydrophilicity and glass transition temperatures. [7][8][9][10][28][29][30] To prepare the [4. The purities of the acetylated polymers were confirmed by 1 H-NMR and 13 C-NMR spectroscopy.…”

Section: Resultsmentioning

confidence: 99%

Glycopolymers Prepared by Alternating Ring-Opening Metathesis Polymerization Provide Access to Distinct, Multivalent Structures for the Probing of Biological Activity

Mendez,

Boadi,

Kennedy

et al. 2024

Preprint

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A myriad of biological processes are facilitated by ligand-receptor interactions. The low affinities of these interactions are typically enhanced by multivalent engagements to promote binding. However, each biological interaction requires a unique display and orientation of ligands. Therefore, the availability and diversity of synthetic multivalent probes are invaluable to the investigation of ligand-receptor binding interactions. Here, we report glycopolymers prepared from bicyclo[4.2.0]oct-6-ene-7-carboxamide and 4,7-dihydro-1,3-dioxepin or cyclohexene. These glycopolymers, synthesized by alternating ring-opening metathesis polymerization, display precise ligand spacing as well as the option of a hydrophobic or acetal-functionalized polymer backbone. Small-angle X-ray scattering (SAXS) data analysis revealed that these [4.2.0] glycopolymers adopted distinct conformations in solution. In aqueous media, [4.2.0]-dioxepin glycopolymers formed swollen polymer chains with rod-like, flexible structures while [4.2.0]-cyclohexene glycopolymers assumed compact, globular structures. To illustrate how these glycopolymers could aid in the exploration of ligand-receptor interactions, we incorporated the [4.2.0] glycopolymers into a biological assay to assess their potential as activators of acrosomal exocytosis (AE) in mouse sperm. The results of the biological assay confirmed that the differing structures of the [4.2.0] glycopolymers would evoke distinct biological responses; [4.2.0]-cyclohexene glycopolymers induced AE in mouse sperm while [4.2.0]-dioxepin glycopolymers did not. Herein, we provide two options for glycopolymers with low to moderate molecular weight dispersities and low cytotoxicity that can be implemented into biological assays based on the desired hydrophobicity, rigidity, and structural conformation of the polymer probe.

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Section: Resultsmentioning

confidence: 99%

Glycopolymers Prepared by Alternating Ring-Opening Metathesis Polymerization Provide Access to Distinct, Multivalent Structures for the Probing of Biological Activity

Mendez,

Boadi,

Kennedy

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

“…The ruthenium-catalyzed AROMP of low-strain cyclic olefins and bicylo[4.2.0]octenes has been investigated extensively and has been championed for producing copolymers that can display a variety of functional groups, controlled backbone sequences, and tunable material properties such as hydrophilicity and glass transition temperatures. − ,− To prepare the [4.2.0] glycopolymers, 4,7-dihydro-1,3-dioxepin or cyclohexene (B monomer) was allowed to react with bicyclo[4.2.0]oct-6-ene-7-carboxamide bearing mannose or fucose (A monomer) in the presence of Grubbs’ third generation catalyst 4 (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

“…The presence of sugar moieties on bicyclo[4.2.0]oct-6-ene-7-carboxamide seemed to significantly lower the reactivity of the reaction, most likely due to steric hindrance as suggested by previous studies. 30,31 Despite allowing the reaction to run for longer than 20 h, copolymers significantly longer than 50 AB units could not be achieved. We have previously demonstrated that polynorbornene 100-mers displaying mannose and fucose efficiently induce AE in mouse sperm 23−25 and polynorbornene 50-mers display the same number of ligands as the [4.2.0] glycopolymers.…”

Section: Design and Preparation Of [420] Glycopolymersmentioning

confidence: 99%

Glycopolymers Prepared by Alternating Ring-Opening Metathesis Polymerization Provide Access to Distinct, Multivalent Structures for the Probing of Biological Activity

Mendez,

Boadi,

Kennedy

et al. 2024

ACS Bio Med Chem Au

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A myriad of biological processes are facilitated by ligand−receptor interactions. The low affinities of these interactions are typically enhanced by multivalent engagements to promote binding. However, each biological interaction requires a unique display and orientation of ligands. Therefore, the availability and diversity of synthetic multivalent probes are invaluable to the investigation of ligand− receptor binding interactions. Here, we report glycopolymers prepared from bicyclo[4.2.0]oct-6-ene-7-carboxamide and 4,7-dihydro-1,3-dioxepin or cyclohexene. These glycopolymers, synthesized by alternating ring-opening metathesis polymerization, display precise ligand spacing as well as the option of a hydrophobic or acetalfunctionalized polymer backbone. Small-angle X-ray scattering (SAXS) data analysis revealed that these [4.2.0] glycopolymers adopted distinct conformations in solution. In aqueous media, [4.2.0]-dioxepin glycopolymers formed swollen polymer chains with rod-like, flexible structures while [4.2.0]cyclohexene glycopolymers assumed compact, globular structures. To illustrate how these glycopolymers could aid in the exploration of ligand−receptor interactions, we incorporated the [4.2.0] glycopolymers into a biological assay to assess their potential as activators of acrosomal exocytosis (AE) in mouse sperm. The results of the biological assay confirmed that the differing structures of the [4.2.0] glycopolymers would evoke distinct biological responses; [4.2.0]-cyclohexene glycopolymers induced AE in mouse sperm while [4.2.0]-dioxepin glycopolymers did not. Herein, we provide two options for glycopolymers with low to moderate molecular weight dispersities and low cytotoxicity that can be implemented into biological assays based on the desired hydrophobicity, rigidity, and structural conformation of the polymer probe.

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“…However, when bicyclo[4.2.0]oct-6-ene-7-carboxamide reacts with the ruthenium benzylidene complex (Chart ), it generates Ru-cyclohexylidene carbene (Figure ). , Although not an α-carbonyl containing carbene, the Ru-cyclohexylidene can react with cyclohexene in the presence of additional bicyclo[4.2.0]oct-6-ene-7-carboxamide monomers to form a linear-alternating copolymer. − To this end, we employed bicyclo[4.2.0]oct-6-ene-7-carboxamide systems in extensive studies because of their fast ROM reactivities compared with previous bicyclo[4.2.0] systems …”

mentioning

confidence: 99%

Long-Range Kinetic Effects on the Alternating Ring Opening Metathesis of Bicyclo[4.2.0]oct-6-ene-7-carboxamides and Cyclohexene

Boadi

Sampson

2023

ACS Org. Inorg. Au

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We report an investigation of rates of ruthenium-catalyzed alternating ring opening metathesis (AROM) of cyclohexene with two different Ru-cyclohexylidene carbenes derived from bicyclo[4.2.0]oct-6-ene-7-carboxamides (A monomer) that bear different side chains. These monomers are propylbicyclo[4.2.0]oct-6-ene-7-carboxamide and N-(2-(2-ethoxyethoxy)ethanylbicyclo[4.2.0]oct-6-ene-7-carboxamide. The amide substitution of these monomers directly affects both the rate of the bicyclo[4.2.0]oct-6-ene-7-carboxamide ring opening and the rate of reaction of the resulting carbene with cyclohexene (B monomer). The resulting Ru-cyclohexylidenes underwent reversible ring opening metathesis with cyclohexene. However, the thermodynamic equilibrium disfavored cyclohexene ring opening. Utilization of triphenylphosphine forms a more stable PPh3 ligated complex, which suppresses the reverse ring closing reaction and allowed direct measurements of the forward rate constants for formation of various A-B and A-B-A′ complexes through carbene-catalyzed ring-opening metathesis and thus gradient polymer structure-determining steps. The relative rate of the propylbicyclo[4.2.0]oct-6-ene-7-carboxamide ring opening is 3-fold faster than that of the N-(2-(2-ethoxyethoxy)ethanylbicyclo[4.2.0]oct-6-ene-7-carboxamide. In addition, the rate of cyclohexene ring-opening catalyzed by the propyl bicyclooctene is 1.4 times faster than when catalyzed by the ethoxyethoxy bicyclooctene. Also, the subsequent rates of bicyclo[4.2.0]oct-6-ene-7-carboxamide ring opening by propyl-based Ru-hexylidene are 1.6-fold faster than ethoxyethoxy-based Ru-hexylidene. Incorporation of the rate constants into reactivity ratios of bicyclo[4.2.0]amide-cyclohexene provides prediction of copolymerization kinetics and gradient copolymer structures.

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Substituent Effects Provide Access to Tetrasubstituted Ring-Opening Olefin Metathesis of Bicyclo[4.2.0]oct-6-enes

Cited by 4 publications

References 35 publications

Glycopolymers Prepared by Alternating Ring-Opening Metathesis Polymerization Provide Access to Distinct, Multivalent Structures for the Probing of Biological Activity

Glycopolymers Prepared by Alternating Ring-Opening Metathesis Polymerization Provide Access to Distinct, Multivalent Structures for the Probing of Biological Activity

Glycopolymers Prepared by Alternating Ring-Opening Metathesis Polymerization Provide Access to Distinct, Multivalent Structures for the Probing of Biological Activity

Long-Range Kinetic Effects on the Alternating Ring Opening Metathesis of Bicyclo[4.2.0]oct-6-ene-7-carboxamides and Cyclohexene

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