Free Radical Reactions on Soluble Supports from Ring-Opening Metathesis

Abstract

[reaction: see text]. Free radical reactions were performed on soluble ring-opening metathesis (ROM) polymers. These polymers have high substrate loading, short reaction times, and the benefit of a facile purification. All reactions on these supports were obtained in good yields as white crystalline-like materials readily separated from tin byproducts.

Thio‐bromo “Click,” post‐polymerization strategy for functionalizing ring opening metathesis polymerization (ROMP)‐derived materials

“…At this time the solvent was removed under reduced pressure, followed by addition of ether. The organic layer was washed with three 30 mL portions of water, dried over Na 2 SO 4 followed by filtration and removal of solvent under reduced pressure to give 1.82 g of yellow oil in 87% yield, 1 H and 13 C NMR spectra are identical to the literature values …”

“…This reaction mixture was allowed to stir for 20 min and then treated with CH 2 Cl 2 (2 mL) and of ethyl vinyl ether (EVE) (2 mL) and was allowed to stir for another 30 min. At this time, the reaction mixture was precipitated in methanol followed by vacuum filtration to provide 2.65 g of 5 as a white precipitate in 91.3% yield; 1 H and 13 C NMR spectra are identical to the literature values . M n = 79,100 Da, M w = 161,000 Da, Đ = 2.03.…”

From Polymer to Small Organic Molecules: A Tight Relationship between Radical Chemistry and Solid-Phase Organic Synthesis

“…Fortunately, in this case a good stereoselectivity (97% ee) was found without any LA addition: this can be explained invoking the Lewis acidity of Bu 3 SnBr (formed during the reaction), which coordinates preferentially to one face of the sugar molecule directing the allyl attack. Enholm studied a series of intermolecular radical reactions also exploiting ROMP polymers [ 87 ] (see below).…”

High-Load, ROMP-Generated Oligomeric Bis-acid Chlorides: Design of Soluble and Insoluble Nucleophile Scavengers

“…Despite these advances, limitations in both nonlinear reaction kinetics and low-load parameters warrant the continued development of new designer polymers in this area. Two common methods have surfaced to address these issues: (1) chemical tagging 6 and (2) the use of soluble, polymeric supports, reagents, and scavenging agents. − Regarding the latter strategy, PEG-based soluble polymers are the most prevalent . Recently, however, a number of alternative systems have emerged, including several dendritic 9 and polyacrylamide 7 systems and a variety of ROMP-derived polymers pioneered by Barrett and co-workers .…”