Highly Tactic Cyclic Polynorbornene: Stereoselective Ring Expansion Metathesis Polymerization of Norbornene Catalyzed by a New Tethered Tungsten-Alkylidene Catalyst
作者:Stella A. Gonsales、Tomohiro Kubo、Madison K. Flint、Khalil A. Abboud、Brent S. Sumerlin、Adam S. Veige
DOI:10.1021/jacs.6b00014
日期:2016.4.20
reacts with CO2, leading to complete cleavage of one C═O bond, followed by migratory insertion to generate the tungsten-oxo alkylidene 2. Complex 2 is the first catalyst to polymerize norbornene via ringexpansion metathesis polymerization to yield highly cis-syndiotactic cyclic polynorbornene.
[EN] CATALYST FOR RING EXPANSION METATHESIS POLYMERIZATION OF CYCLIC MONOMERS<br/>[FR] CATALYSEUR POUR LA POLYMÉRATION PAR MÉTATHÈSE AVEC EXPANSION DE CYCLE DE MONOMÈRES CYLCIQUES
申请人:UNIV FLORIDA
公开号:WO2017049270A1
公开(公告)日:2017-03-23
A tetraanionic OCO pincer ligand metal-oxo-alkylidene complex is prepared from a trianionic pincer ligand supported metal-alkylidyne. The metal can be tungsten or other group 5-7 transition metal. The tetraanionic pincer ligand metal-oxo-alkylidene complex, a trianionic OCO pincer ligand metal complex, or a trianionic ONO pincer ligand metal complex can be used to polymerize cycloalkenes. The poly(cycloalkene)s are predominantly cis-alkene macrocyclics.
Diastereoselective addition of monoterpenic alcoholates and thiolates to 2,3-dicarbomethoxynorbornadiene
作者:Ivan Michieletto、Fabrizio Fabris、Ottorino De Lucchi
DOI:10.1016/s0957-4166(00)00231-7
日期:2000.7
Addition of excess lithium salts of (−)-menthol or (−)-borneol to 2,3-dicarbomethoxynorbornadiene 1 affords the transesterification–addition products 4 and 5. The thiols derived from the same monoterpenes give only the addition products to the activated double bond, 6 and 7. In all cases, the addition reaction is totally exo-selective with respect to the norbornadiene moiety and moderately selective