ORGN 554 |
| Terminally functionalized polyisobutylene (PIB) oligomers can be easily transformed into a library of end-functionalized PIB oligomers. Previous work has shown that PIB oligomers possess enough non polar characteristics that allow them to be used as phase tags for various ligands and catalysts. These non polar labeled materials can be utilized and recycled in various biphasic liquid/liquid solvent systems. This presentation will describe the use of vinyl terminated functionalized PIB oligomers in electrophilic aromatic substation reactions with electron rich arenes such as tert-butyl phenol and phenol. The product PIB attached tert-butyl phenol can be further formylated with para-formaldehyde to form precursors for Salen ligands for metals like Cr(III). The resulting metal complexes function like their low molecular weight counterparts as evidenced by reactions where they were successfully used as recyclable catalysts for ring opening of epoxides with thiols. PIB-bound phenol can also be formylated, alkylated with 2-iodopropane, and converted into a styrene using Wittig chemistry. The product PIB-bound o-isopropyloxystyrene can then be converted into a 2nd Generation Hoveyda-Grubbs catalyst that is phase selectively soluble in heptane. Examples where this PIB-supported Hoveyda-Grubbs ruthenium catalyst are used both for ring-opening polymerizations and-ring closing metathesis will be described. |
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Physical Organic Chemistry, Metal-Mediated Reactions, Asymmetric Reactions and Syntheses
8:00 PM-10:00 PM, Tuesday, August 21, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Organic Chemistry |