A Convenient Method for Removing All Highly-Colored Byproducts Generated during Olefin Metathesis Reactions

Abstract

[formula: see text] Addition of a very modest amount of lead tetraacetate (1.50 equiv relative to the amount of Grubbs catalyst) to ring-closing metathesis reaction mixtures effectively removes all colored ruthenium and phosphine impurities to deliver colories reaction products.

Efficient metal‐free coupling of polystyrene chains using silane radical atom abstraction

“…[32][33][34][35][36] In the case of ATRC, an excess of metal is used to alter an unfavorable equilibrium and create a buildup of the polymer radicals, which is essential for the bimolecular coupling reaction to proceed at a suitable rate yet otherwise unfavorable in the preparation of polymeric materials. In this contribution, silane radical atom abstraction (SRAA, Scheme 2) is introduced as a metal-free alternative to generate polystyrene (PSt) of controllable molecular weights and low PDI values by coupling of polymer radicals generated from monobrominated polystyrene (PStBr) precursors.…”

Total Synthesis of (±)‐Haliclonacyclamine C

“…While all are viable methods, we were discouraged by both the methods developed by Grubbs and Paquette. 149,150 The Grubbs method involved using tris(hydroxymethyl)phosphine to react with residual ruthenium by-products that would later be removed during aqueous work-up. However, tris(hydroxymethyl)phosphine is an extremely expensive reagent and we sought other means to remedy this problem.…”

Ruthenium‐Catalyzed Ring‐Closing Metathesis: Recent Advances, Limitations and Opportunities

“…Additives used to modify or sequester the spent ruthenium following RCM with C1a include lead tetraacetate [171], DMSO or triphenylphosphine oxide [172], or water-soluble phosphines [173]. An interesting new approach is the use of a polymer-bound diarylphosphine scavenger [174].…”