The Total Synthesis of (-)-Prezizaene, (-)-Prezizanol, and Other Perzizanoid Sesquiterpenes

The synthesis of four related sesquiterpenes was accomplished by elaboration of the chiral precursor pulegone. The ring system of (-)-prezizaene and (-)-prezizonal was constructed by intramolecular ring expansion of a diazo ethyl hydrindanone. (-)-Georgeone and (-)-georgeol containing a C-6 methyl group were formed by pinacolic rearrangement of a 3a,6-ethanoindene-diol. Favorskii rearrangement of (+)-pulegone and ozonolysis furnished ethyl 5-methyl-2-oxo-cyclopentane carboxylate which was annelated with methyl vinyl ketone to give a mixture of diastereomeric hydrindenones. Hydrogenation to ethyl 3-methyl-6-oxo-cis-hexahydroindane-3a-carboxylate was stereospecific. Ketone protection, reduction of the ester and sulphonylation gave 7a-hydroxymethyl-1-methyl-cis-hexahydroindane-5-one ethylene ketal as a single isomer after crystallization. An X-ray structure determination confirmed the all cis stereochemistry at the three chiral centers. Reduction and hydrolysis afforded a dimethyl ketone which was identical with a sample prepared independently.

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

• Roach, Paula Marianne

• Chemistry, Organic

Language dc:language

eng

Identifier

(UMI)AAI8127678

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/67281