Synthesis of the Ophiobolin Ring System

The synthesis of 1-oxo-1H-dicyclopenta(a,d)-5-carboxylates developed in these laboratories by Senter, Baker, and Coates has been extended to a synthesis of a 5-8-5 ring system having the relative configuration of the ophiobolin and ceroplastol sesterterpenes. The relative stereochemistry of three of the four asymmetric centers was determined by x-ray crystallographic analysis of an intermediate iodide. Incorporation of a (DELTA)('7,8) double bond, which is a structural feature common to most ophiobolins and ceroplastols, was effected by dehydroiodination of an intermediate iodo ketone that was prepared in one step from the corresponding dicyclopentacyclooctene carboxylic acid. A 5-8-5 ring system with the relative configuration of the fusicoccin family of diterpenes at C-6, C-7, and C-11 was also synthesized by the same annelative two-carbon ring expansion of an unsubstituted trans-hydrindanone. Analysis of the chemistry of these 5-8-5 ring systems was simplified since most chemical transformations were carried out on single diastereomers of known relative stereochemistry.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Muskopf, Jack Warren

• Chemistry, Organic

Identifier

(UMI)AAI8409813

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/70238