The development of tandem reactions involving enyne metathesis to form substituted cyclic dienes
Schertzer, Bryan Michael
MetadataShow full item record
Enyne metathesis provides direct access to conjugated 1,3 dienes of varying substitution patterns under mild conditions. Our primary focus involves enyne metathesis catalyzed by the Grubbs-type carbene complexes. The combination of enyne metathesis with other reactions in either a tandem or sequential fashion extends the utility of this methodology. Of particular interest is the combination of enyne cross metathesis and ring closing olefin metathesis in dienyne systems to create cyclic dienes. A current perception in enyne metathesis is that the incorporation of heteroatoms in the allylic position of the olefin can be problematic. We are interested in the development of a tandem enyne cross metathesis/ring closing metathesis reaction involving meso -1,5-hexadiene-3,4-diols to provide a synthetic access to chiral cyclohexadiene diols. Another interest in our group is the development of chiral ruthenium catalysts for the desymmertization of meso dienes in the tandem reaction. The first part of this thesis will describe our study of N -heterocyclic carbenes, the development of a chiral N -heterocyclic carbene and the progress toward a chiral ruthenium complex incorporating the chiral carbene ligand. The second part of the thesis will cover the synthesis of the meso diene diol substrates and the evaluation of their use in intermolecular tandem enyne cross metathesis/ring closing metathesis. The development of an intramolecular tandem enyne metathesis/ring closing metathesis with vinyl siloxyalkynes will also be discussed. Finally, the utilization of a tandem sequential enyne metathesis/Ireland ester enolate Claisen reaction to synthesize a chiral, 4-substituted cyclohexadiene diol will be illustrated.