Use this URL to cite or link to this record in EThOS: | https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373205 |
![]() |
|||||||
Title: | Synthetic studies towards pinguisone | ||||||
Author: | Webster, Nigel Martin Henry |
ISNI:
0000 0001 3565 167X
|
|||||
Awarding Body: | University of Southampton | ||||||
Current Institution: | University of Southampton | ||||||
Date of Award: | 1986 | ||||||
Availability of Full Text: |
|
||||||
Abstract: | |||||||
The novel structure and antifeedant activity of the furanosesquiterpene pinguisone make it an interesting synthetic target. The approach described in this work involves a [4+2]cycloaddition as the key reaction in constructing the correct indene skeleton. Whereas 1-methoxy-3-trimethyl-siloxybuta-1,3-diene (Danishefsky's diene) was completely unreactive towards 2,3,4-trimethyl-2-cyclopentenone, Diels-Alder cycloaddition was found to occur at very high pressure (13-15 kBar) with the more reactive dienophile methyl 2,3-dimethyl-5-oxo-1-cyclopentene-1-carboxylate giving after hydrolysis (3R*,3aS*,7aR*)-methyl 3,3a-dimethyl-1,5(4H)-dioxo-2,3,3a,7a-tetrahydroindene-7a-carboxylate in good yield. The structure of this was confirmed by X-ray diffraction. Reaction of the lithium enolate of the diene with the more reactive dienophile at low temperatures gave one Michael addition only; however, the resulting ketoester was converted to the desired indene intermediate in a good overall yield. Model studies provided a route which when applied to the indene intermediate enabled an efficient conversion (3R*,3aS*,7aS*)-2,3,3a-7a-tetrahydro-3,3a,7a-trimethylindene-1,5(4H)-dione. Conjugate addition with lithium dimethylcuprate gave the undesired epimer exclusively which on further elaboration gave 4-epipinguisone and 4-epipinguisanol.
|
|||||||
Supervisor: | Not available | Sponsor: | Not available | ||||
Qualification Name: | Thesis (Ph.D.) | Qualification Level: | Doctoral | ||||
EThOS ID: | uk.bl.ethos.373205 | DOI: | Not available | ||||
Keywords: | Organic chemistry | ||||||
Share: |