3604-36-2Relevant articles and documents
Radical polymerization of 2,5-norbornadienes containing ester groups by AIBN and oxygen gas
Shiotsuki, Masashi,Kai, Hironobu,Endo, Takeshi
, p. 2528 - 2536 (2014)
New 2,5-norbornadiene-type monomers bearing 1-adamantyl and cyclohexyl ester groups on their 2-position polymerized with azobisisobutyronitrile to form the polymers consisting of two types of polymer unit structures. The major part had a saturated nortricyclene framework, which was formed by 2,6-addition along with intramolecular cyclization on the norbornadiene moiety. The minor part consisted of 2-norbornene-type units constructed via 2,3-addition. A series of norbornadiene-based monomers spontaneously polymerized in the presence of oxygen. Because a radical inhibitor, namely hydroquinone, could suppress this spontaneous reaction, it was indicated that the oxygen-induced polymerization proceeds via free-radical polymerization mechanism. Changing a quantity of provided oxygen gas (O2) to a norbornadiene monomer significantly affected on polymerization results, in specific, molecular weight of the formed polymer, which indicated that oxygen serves as one of the key reagents for the formation of free-radical initiating species. It was proven that the combination of norbornadiene ethyl ester with O2 was applicable as a new free-radical initiator for polymerization of methyl methacrylate.
Photoinduced intramolecular cyclopentanation vs photoprotolytic oxametathesis in polycyclic alkenes outfitted with conformationally constrained aroylmethyl chromophores
Valiulin, Roman A.,Arisco, Teresa M.,Kutateladze, Andrei G.
, p. 2012 - 2025 (2013/05/21)
Intramolecular photoinduced cyclizations are investigated in photoprecursors assembled in a modular fashion via a Diels-Alder reaction of acetylenic dienophiles with subsequent Michael additions of aromatic ketones to install a chromophore capable of initiating Paternò-Büchi cycloadditions or radical cyclization cascades. The protolytic oxametathesis in these systems allows for rapid access to novel polycyclic scaffolds decorated by formyl groups and carboxylates suitable for subsequent modifications. In conformationally constrained photoprecursors, a radical rearrangement takes place resulting in intramolecular 1,3-diradical cyclopentanation of the double bond.
Synchronous enantiomeric enrichment of both reactant and product by absolute asymmetric synthesis using circularly polarized light. Part 3. Numerical simulation and experimental verification of the reversible asymmetric photoisomerization between methyl norbornadiene-2-carboxylate and methyl quadricyclane-1-carboxylate
Nishino,Nakamura,Shitomi,Onuki,Inoue
, p. 1706 - 1713 (2007/10/03)
In the first paper of this series, we proposed a new absolute asymmetric synthesis (NAAS) with circularly polarized light (CPL), which can be classified into two subcategories: (a) reversible NAAS (CPL excites both the reactant and product), (b) irreversible NAAS (the reactant only is excited by CPL). In the present paper we deal with reversible NAAS. The numerical simulations, which are based upon the results of the preceding paper of this series, are performed. Using the reversible photoisomerization between methyl norbornadiene-2-carboxylate (I) and methyl quadricyclane-1-carboxylate (II), it was experimentally verified that the enantiomeric excesses (ee's) of both the reactant and product were critically dependant not only on the anisotropy factors (g = Δε/ε) of both components, but also on the relative quantum yields of the forward and reverse reactions. In the case of reversible NAAS, the ee of the reactant and the product will concurrently increase according to the conversion, and attain appreciable values at the photostationary state if we appropriately select the system and the CPL-irradiation wavelength in such a way that if the g factors of the product and the reactant are large enough, the sign of the g factor of the product is opposite to that of the reactant, and the photochemical equilibrium constant K is less than unity.
