Department of Chemistry   University of Oxford
Inorganic Chemistry Laboratory
MLH Green Lecture Symposium

The MLH Green Lecture Symposium for 2011 took place on the 14th March. The keynote lecture was given by Richard R Schrock, the Frederick G. Keyes Professor of Chemistry and winner of the 2005 Nobel Prize. Supporting lectures were given by Fraser Armstrong FRS (RSC Joseph Chatt Award winner 2010) and Simon Aldridge (RSC Main Group Chemistry Award winner 2010)

Richard R Schrock was talk on "The Unique Abilities of MAP Catalysts for Olefin Metathesis"
Abstract "Third generation" M(NR)(CHCMe2R')(OR)(Pyr) (MonoAlkoxidePyrrolide or MAP) species can be remarkably active and efficient olefin metathesis catalysts. The advantages of a stereogenic metal center for enantioselective metathesis has been demonstrated through the synthesis of diastereomeric M(NR)(CHCMe2R')(OR*)(Pyr) species in which OR* is an enantiomerically pure aryloxide, and its use (as a mixture of diastereomers) as a catalyst for the enantioselective synthesis of the Aspidosperma alkaloid, quebrachamine (96%ee). MAP species also have characteristics that make them unique in other reactions, among them Z- and enantioselective ring-opening/cross-metatheses, ethenolysis of internal olefins such as oleates, Z-selective coupling of terminal olefins, and Z-selective cross coupling of terminal olefins. Z-selective catalysts also can be employed to make ROMP polymers from norbornenes and substituted norbornenes that have a single structure. A key aspect of MAP catalysts is inversion of configuration at the metal center with each monomer insertion, what we call "stereogenic metal control," which is a new way to control polymer structure. Polymerization of racemic 5,6-disubstituted norbornenes also can lead to cis,syndiotactic polymers with a perfectly "alternating enantiomer" structure, a type of polymer that is virtually unknown.

Schrock
Schrock Schrock

 

 


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