339540-96-4Relevant academic research and scientific papers
Tandem ring-opening/ring-closing metathesis polymerization: Relationship between monomer structure and reactivity
Park, Hyeon,Lee, Ho-Keun,Choi, Tae-Lim
, p. 10769 - 10775 (2013/08/23)
Monomers containing either cycloalkenes with low ring strain or 1-alkynes are poor monomers for olefin metathesis polymerization. Ironically, keeping two inactive functional groups in proximity within one molecule can make it an excellent monomer for metathesis polymerization. Recently, we demonstrated that monomer 1 having cyclohexene and propargyl moieties underwent rapid tandem ring-opening/ring-closing metathesis (RO/RCM) polymerization via relay-type mechanism. Furthermore, living polymerization was achieved when a third-generation Grubbs catalyst was used. Here, we present a full account on this tandem polymerization by investigating how various structural modifications of the monomers affected the reactivity of the tandem polymerization. We observed that changing the ring size of the cycloalkene moieties, the length of the alkynes, and linker units influenced not only the polymerization rates but also the reactivities of Diels-Alder reaction, which is a post-modification reaction of the resulting polymers. Also, the mechanism of tandem polymerization was studied by conducting end-group analysis using 1H NMR analysis, thereby concluding that the polymerization occurred by the alkyne-first pathway. With this mechanistic conclusion, factors responsible for the dramatic structure-reactivity relationship were proposed. Lastly, tandem RO/RCM polymerization of monomers containing sterically challenging trisubstituted cycloalkenes was successfully carried out to give polymer repeat units having tetrasubstituted cycloalkenes.
ROM-RCM of cycloalkene-yne
Kitamura, Tsuyoshi,Kuzuba, Yuichi,Sato, Yoshihiro,Wakamatsu, Hideaki,Fujita, Reiko,Mori, Miwako
, p. 7375 - 7389 (2007/10/03)
Ring-opening metathesis and ring-closing metathesis (ROM-RCM) of cycloalkene-yne was demonstrated using a first- or second-generation ruthenium complex. When cycloalkenes bearing the alkyne part at the C-3 position were reacted with a first-generation ruthenium-carbene complex under an atmosphere of ethylene, ROM-RCM proceeded smoothly to give skeletal reorganized products in good yields. In this reaction, cycloalkene-ynes having terminal alkyne were suitable. On the other hand, when cycloalkenes bearing the alkyne part at the C-1 position were treated with a second-generation ruthenium-carbene complex, ROM-RCM proceeded smoothly to give bicyclic compounds and/or dimeric compounds in good yields.
