18913-31-0Relevant articles and documents
RAFT polymerization of a novel allene-derived asymmetrical divinyl monomer: A facile strategy to alkene-functionalized hyperbranched vinyl polymers with high degrees of branching
Bao, Youmei,Shen, Guorong,Liu, Xiaohui,Li, Yuesheng
, p. 2959 - 2969 (2013)
Hyperbranched vinyl polymers with high degrees of branching (DBs) up to 0.43 functionalized with numerous pendent allene groups have been successfully prepared via reversible addition fragmentation chain transfer polymerization of a state-of-art allene-derived asymmetrical divinyl monomer, allenemethyl methacrylate (AMMA). The gelation did not occur until high monomer conversions (above 90%), as a result of the optimized reactivity difference between the two vinyl groups in AMMA. The branched structure was confirmed by a combination of a triple-detection size exclusion chromatography (light scattering, refractive index, and viscosity detectors) and detailed 1H NMR analyses. A two-step mechanism is proposed for the evolution of branching according to the dependence of molecular weight and DB on monomer conversion. Controlled radical polymerization proceeds until moderate conversions, mainly producing linear polymers. Subsequent initiation and propagation on the polymerizable allene side chains as well as the coupling of macromolecular chains generate numerous branches at moderate-to-high monomer conversions, dramatically increasing the molecular weight of the polymer. AMMA was also explored as a new branching agent to construct poly(methyl methacrylate)-type hyperbranched polymers by its copolymerization with methyl methacrylate. The DB can be effectively tuned by the amount of AMMA, showing a linear increase trend. The pendent allene groups in the side chains of the copolymers were further functionalized by epoxidation and thiol-ene chemistry in satisfactory yields.
Formation of 6-Azaindoles by Intramolecular Diels-Alder Reaction of Oxazoles and Total Synthesis of Marinoquinoline A
Jhaveri, Dishit P.,Osano, Mana,Wipf, Peter
supporting information, p. 2215 - 2219 (2020/04/09)
A new variant of the intramolecular Diels-Alder oxazole (IMDAO) cycloaddition that provides direct access to 6-azaindoles was developed. The IMDAO reaction was applied in a total synthesis of the aminophenylpyrrole-derived alkaloid marinoquinoline A, also
Dearomative Cycloadditions Utilizing an Organic Photosensitizer: An Alternative to Iridium Catalysis
Rolka, Alessa B.,Koenig, Burkhard
supporting information, p. 5035 - 5040 (2020/07/15)
A highly efficient, cheap, and organic alternative to the commonly used iridium photosensitizer (Ir[dF(CF3)ppy]2(dtbpy))PF6 ([Ir-F]) is presented for visible-light energy transfer catalysis. The organic dye 2CzPN surpasses [Ir-F] in selectivity while at t
