Journal of the American Chemical Society, Vol.138, No.15, 4996-4999, 2016
Highly Tactic Cyclic Polynorbornene: Stereoselective Ring Expansion Metathesis Polymerization of Norbornene Catalyzed by a New Tethered Tungsten-Alkylidene Catalyst
The tungsten alkylidyne [(BuOCO)-Bu-t]W C(Bu-t) (THF)(2) (1) 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 norbomene via ring expansion metathesis polymerization to yield highly cis-syndiotactic cyclic polynorbornene.