Highly diastereoselective epoxidation of cholest-5-ene derivatives catalyzed by polymer-supported manganese(III) porphyrins

Immobilization of metallporphyrins on polystyrene: Efficient catalysts for aerobic oxidation of alcohols

“…Such polymer supported MPs possess several advantages over conventional homogeneous catalysts, such as, possibility of better and easy workup, recyclability and controllability of microenvironments. In few recent reports [16,17], MPs have been successfully anchored on polymer matrix, but they are scarcely [18] used for aerobic oxidations of alcohols. During catalytic oxidations using MPs, under homogeneous conditions, we come across problems such as catalyst separation, dimerization and destruction due to self-oxidation.…”

Homogeneous and Heterogeneous Free-Based Porphyrins Incorporated to Silica Gel as Fluorescent Materials and Visible Light Catalysts Mimic Monooxygenases

“…Tangestaninejad et al have described the tetra(4-pyridyl)porphyrinato manganese(III) anchored in chloromethylated styrene-divinylbenzene copolymer as an efficient and reusable catalyst for the (R)-(+)-limonene epoxidation by sodium periodate, among several other alkenes (Moghadam et al, 2004). The Chinese team has utilized manganese(III) 5,10,15-tris(tolyl)-20-(4-hydroxyphenyl) porphyrin covalently attached to the Merrifield's peptide resin for the highly diastereoselective epoxidation of cholest-5-ene derivatives (Du, et al, 2004). The similar sort of material has been used by Gonsalves et al (2008) in photooxidation of monoterpenes.…”

Polystyrene microsphere-immobilized palladium(II) porphyrin as mild, reusable, and highly efficient catalyst for Heck reaction

“…The palladium levels in the products were lower in these systems than in homogeneous systems, but the catalytic activities decrease gradually in the recycled systems. This might be because of weak coordination between palladium and the ligands, leading to palladium leaching (Mahdavi, Zirakzadeh, & Amani, 2007;Pathan & Patel, 2012;Zhao, Murakami, Shirai, & Arai, 2000), or failure to provide a hydrophobic microenvironment for the active sites of the catalyst (Du et al, 2004).…”

“…A suitable microenvironment not only effectively prevents destruction and deactivation of the palladium-porphyrin catalyst by self-oxidation and aggregation through p-p interactions, but also enhances the catalytic activity (Du et al, 2004;Gotardoa et al, 2005;Lindsay Smith, Iamamoto, & Vinhado, 2006;Rebelo et al, 2006).…”