Access to Bicyclo[4.2.0]octene Monomers To Explore the Scope of Alternating Ring-Opening Metathesis Polymerization

Abstract

Bicyclo[4.2.0]oct-1(8)-ene-8-carboxamides undergo alternating ring-opening metathesis polymerization (AROMP) with cyclohexene. Herein, a general method for the preparation of bicyclo[4.2.0]oct-(8)-ene-8-carboxy derivatives is described. The central 8-cyano intermediate provides entry to five different functional group substituents on the alkene. These monomers were tested as potential substrates for AROMP with cyclohexene. In addition to the carboxamide, the carboxynitrile and carboxaldehyde are also substrates for AROMP. In the case of the carboxaldehyde, the polymer is regioregular. However, the addition of carboxynitrile is stereoirregular and slow.

Ruthenium‐Catalyzed Alternating Ring‐Opening Metathesis Copolymerization of Norborn‐2‐ene with Cyclic Olefins

“…[1,2] However, the synthesis of precision polymers [1b] derived from the alternating copolymerization of two different monomers via ROMP, promoted by ruthenium-based catalysts, is still limited. [3][4][5][6][7][8][9] Only a few examples of alternating ROMP copolymers obtained using properly designed catalysts have been reported. [4][5][6][7] Chen and coworkers developed first generation ruthenium catalysts with modified, unsymmetrical steric environment around the metal center by introducing chelating phosphine/phenolate ligands.…”

Alternating Ring-Opening Metathesis Polymerization (AROMP) of Hydrophobic and Hydrophilic Monomers Provides Oligomers with Side-Chain Sequence Control

“…Monomer 1 was prepared as reported. 21,23 Cyclohexene 2 was distilled from CaH 2 prior to use. The synthesis of catalyst (3-Br-Pyr) 2 Cl 2 (H 2 IMes)Ru=CHPh, 3 , was performed according to the procedure of Love et al 24…”

Alternating Cascade Metathesis Polymerization of Enynes and Cyclic Enol Ethers with Active Ruthenium Fischer Carbenes

“…Ring-opening metathesis polymerization (ROMP) has become one of the most efficient methods to construct olefinic polymers containing an impressive range of functionalities. − Recently, efforts in metathesis polymerization have been directed toward advancing the backbone chemistry of metathesis-derived materials to introduce labile functionality or sequences into the polymer backbone. − Several strategies have been employed to generate degradable metathesis systems including ROMP of bicyclic scaffolds, , acyclic diene metathesis, , entropy-driven ROMP, − and cascade enyne metathesis polymerization. , An alternative approach is to combine low to moderately strained cycloolefins with highly strained monomers in copolymerization reactions. − While the low-strain monomers generally display poor homopolymerization behavior, they can enable the introduction of labile functionality, such as silyloxides or acetals. , If these systems copolymerize randomly or in an alternating fashion, materials are produced that can degrade to low molecular weight small molecules and oligomers. Here, we report a new strategy for alternating ring-opening metathesis polymerization (AROMP) of entirely low-strain monomers that relies on the unique reactivity of Fischer-type ruthenium alkylidenes.…”