Chemoselective ring-opening metathesis polymerization of cyclopropenes spirally appended with N-aryl saturated heterocycles

Abstract

The nature of the substituents on the cyclopropenes and the catalysts could have a profound effect on the reactivity and selectivity of ring-opening metathesis polymerization (ROMP). We have previously reported...

Recovery of Homogeneous Platinoid Catalysts from Pharmaceutical Media: Review on the Existing Treatments and the Perspectives of Membrane Processes

“…Reductive elimination is favored but the oxidative addition step is limited because of the accessibility around the metal center. This change may therefore result in a decreasing reaction yield or even the formation of a different synthesized molecule [ 109 ]. This strategy could be balanced by rising the quantity of catalysts used for the reaction but only if the recovery and reuse are enough to make it economically viable.…”

Palladium-Catalyzed Cross-Coupling Polymerization of Bis-N-tosylhydrazones and Bis(silyl) Aryls: A New Access to Polycarbosilane Synthesis

“…The development of novel polymerization methods and related processes is of great importance in enriching the diversity of polymer science and accessing various functional materials. − As one of the most important families of functional materials, organosilicon polymers have been widely applied in adhesives, coatings, ceramics, moldings, and sealing materials. − In particular, polycarbosilanes containing Si–C bonds in polymer backbones have received extensive investigation due to their low toxicity, high chain flexibility, and excellent thermal and oxidative resistance. ,− The catalytic synthesis of polycarbosilanes traditionally relies on the hydrosilylation polymerization of alkenes and silanes, typically by Pt-based catalysts such as Speier’s and Karstedt’s catalysts. − More recently, rare earth metal catalysis, early transition-metal catalysis, , borane-based catalysis, , and photocatalysis , have emerged as new tools (Scheme a). In contrast to widely investigated hydrosilylation polymerization of alkenes, in which regioselectivity issues should be taken into consideration, other strategies are much less exploited and developed …”