Synthesis and catalytic activity of supported acenaphthoimidazolylidene N-heterocyclic carbene ruthenium complex for ring closing metathesis (RCM) and ring opening metathesis polymerization (ROMP)

Abstract

Ruthenium catalyzed ring closing metathesis (RCM) and ring opening metathesis polymerization (ROMP) reactions using a PIB-supported bis(arylimino)acenaphthene (BIAN) complex has been reported. The BIAN Ru-complex exhibits excellent catalytic activity and tolerates a wide range of substrates at low catalyst loadings. DFT calculations were also carried out on some selected key intermediates in the reaction mechanism to study the effect of having the conjugated aromatic moiety (BIAN ligand) in the backbone of the complex. The newly synthesized PIB-BIAN Ru-complex shows comparable catalytic activities to the commercially available second generation Hoveyda-Grubbs catalyst. The recycled complex was reused for up to eight reaction cycles for the RCM of N,N-diallyl tosylamine affording high average isolated yield.

Ring opening metathesis polymerization (ROMP) of five‐ to eight‐membered cyclic olefins: Computational, thermodynamic, and experimental approach

“…While there have been many reports documenting the ROMP of norbornene derivatives, there are surprisingly few examples of ROMP of low‐strain cyclic olefins using ruthenium catalysts. For example, Grubbs and coworkers reported the ROMP of cyclopentene and cycloheptene, the ROMP of cis , cis ‐cycloocta‐1, 5‐diene (COD), and ROMP of hydroxyl‐ or acetate‐disubstituted cyclopentene .…”

Phase‐Separable Polyisobutylene Palladium‐PEPPSI Precatalysts: Synthesis and Application in Buchwald–Hartwig Amination

“…During our study, we carried out the synthesis of 5a and 5b by employing the conventional synthetic procedure, starting from the corresponding imidazolium salts 4a and 4b . The titled ligands 4a and 4b were prepared according to the literature procedures, starting from their corresponding anilines ( Scheme ). The three‐step procedure leading to 5a and 5b was found to be straightforward, resulting in the desired crude complexes.…”

“…Several reports exploiting its prosperous features have recently been reported on the backbone‐site sterically hindered BIAN‐NHC containing Pd‐PEPPSI complexes . The concept of using soluble polymers for their phase‐selective solubility, pioneered by Bergbreiter, has attracted several research groups' attention, describing various polymer‐tagged organometallic complexes to date in the literature . The primary significance of tagging relies on the aforementioned phenomenon, i.e., the complexes became selectively soluble in the heptane phase of a biphasic heptane/polar solvent mixture, facilitating the separation (in some cases the recycling) of the employed catalyst/complex .…”

Synthesis of thioether‐functional poly(olefin)s via ruthenium‐alkylidene initiated ring‐opening metathesis polymerization

“…Ring‐opening metathesis polymerization (ROMP) is one of the most feasible and versatile methods for preparing essential functional poly(olefin)s . Since the discovery of the ROMP of norbornene using RuCl 3 ‐based catalyst, numerous examples of ROMP of functionalized or nonfunctionalized cycloolefins in the presence of well‐defined Grubbs or Hoveyda–Grubbs type ruthenium‐alkylidene complexes have been reported . Owing to their exceptional catalyzing propensity, stability toward harsh reaction conditions and excellent functional group tolerance, ruthenium‐alkylidene complexes have the ability to induce living or even controlled polymerizations …”

“…Recently, our group evaluated the ROMP reactivity for various functional and nonfunctional five‐ to eight‐membered cycloolefins, thus affording a new class of structurally well‐defined poly(olefin)s . In addition, our group has also investigated ROMP of bicycloolefins initiated by well‐modified polymer supported phase separable Grubbs and Hoveyda–Grubbs catalysts . Our attempts overall have furnished a series of functional poly(olefin)s based on polypentenamers, poly(vinyl alcohol)s, and poly(norbornene)s .…”