Towards polymer-supported Schrock-type initiators for olefin metathesis
This thesis describes the synthesis of supported Schrock-type initiators immobilised via polymer-bound alcohol and their activity in olefin metathesis, together with a parallel study of the synthesis and reactivity of their model homogeneous counterparts.;Chapter 1 presents an overview of the inorganic and organic supports used in order to achieve the heterogeneisation of a range of different homogenous catalysts. A review of the nature of various organic supports and examples of supported metalligand complexes are given. The terms olefin metathesis, and their corresponding metathesis reactions such as ROMP, RCM, ADMET, ROM, and cross metathesis are defined. A review of previously reported classical multi-component initiator systems, well-defined single component initiators, together with well-defined supported initiators for use in olefin metathesis reactions is given.;Chapter 2 describes the synthesis of diol ligands such as TADDOL and those based upon a pentanediol skeleton together with that of their supported counterparts. The synthesis of supported tetrafluorophenol via microwave-assisted Suzuki-Miyaura cross coupling is discussed. Strategies for the synthesis of polymer supports bearing TADDOL, pentanediol, and tetrafluorophenol unist with a built-in 'spacer' are examined.;Chapter 3 describes the synthesis of new Schrock-type olefin metathesis initiators, based on discrete soluble ligands described in chapter 2. Their formation is monitored by VT-NMR 1H NMR experiments. Evidence of the ring-closing metathesis reactivity of the newly synthesised Schrock initiators is presented.;Chapter 4 describes the synthesis of polymer-supported Schrock-type olefin metathesis initiators based on resins outlined in chapter 2. The activity of such supported initiator system for ring-closing metathesis is examined. Strategies for the "on-beads" synthesis of a Schrock-type metathesis initiator are discussed.