Total synthesis of the proposed structure of sclerophytin F and structure re-evaluation

QD Chemistry

Delion, Laëtitia ; Clark, J. Stephen

University:University of Glasgow

Department:School of Chemistry

关键词: Sclerophytin, natural product, total synthesis, structure elucidation;   

Others  :  http://theses.gla.ac.uk/5926/7/2014delionphd.pdf

来源: University of Glasgow

【 摘 要 】

The thesis presents the first enantioselective synthesis of the proposed structure of sclerophytin F and consequently, the first total synthesis of a cladiellin family member having the S-configuration at the C-3 stereocentre. Three novel enantioselective routes are described to access a pivotal intermediate; then, the synthesis follows three key steps: i) radical-mediated cyclisation, ii) oxonium ylide formation and [2,3]-sigmatropic rearrangement, iii) Diels-Alder cycloaddition to deliver the core of the natural product. The novelty of the route relies on the introduction of the C-3 methyl group at an early stage of the synthesis. As anticipated, the presence of this extra methyl had significant influence on many transformations. Finally, the elaboration of the core to meet the proposed structure was completed. Unfortunately, none of the recorded data matched those originally reported for the natural compound. A further three stereoisomers were synthesised but their data also did not match the original.