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Studies of Some Strained-Ring Systems: Tricyclo-Octanes

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posted on 2021-11-05, 02:55 authored by Banwell, Martin Gerhardt

The present study has been directed towards the synthesis and base promoted rearrangements of some saturated and unsaturated halogenotricyclo-octanes. The preparation of a number of previously unknown 4,4,8- and 4,4,8,8-tetra-halogeno-anti-tricyclo[5,1,0,03,5]- octanes and the corresponding 3,3,8-tri- and 3,3,8,8-tetra-halogeno-anti-tricyclo[5,1,0,02,4] octanes has been accomplished and the stereo-chemistries of their ring systems established. The former tricyclo-octanes are base sensitive and on treatment with potassium t-butoxide give rise to mixtures of (E) - and (Z) -Beta-t-butoxystyrenes. However, the anti-tricyclo[5,1,0,02,4] octanes give no characterisable products on treatment with base. The mechanistic implications of the tricycle-octane - styrene conversion have been studied in some detail and halogenocyclo-octatetraenes and phenylacetylenes have been eliminated as intermediates. The behaviour of several methoxy-substituted 4,4,8,8-tetrahalogeno-anti-tricyclo[5,1,0,03,5] octanes with the same base has been studied, and it has been found that homotropilidenes are formed regiospecifically by 1,4-elimination. These conversions constitute the first known examples of such elimination experienced by ring-fused halogenocyclopropanes. From these studies, evidence is presented which implicates homotropilidenes and bicyclo[4,2,0]octa-2,4-dienes as intermediates in the production of styrenes, and a mechanism for the tricyclo-octane - styrene rearrangement has been proposed. A new and potentially versatile synthesis of 3,3-dihalogeno-anti tricyclo[5,1,0,02,4] oct-5-enes (anti-bishomobenzenes) has been developed. The new route employs readily available starting materials, involves sequential introduction of the cyclopropyl, gem-dihalogenocyclopropyl, and olefinic moieties and proceeds in an overall yield of about 14%. This represents a five-fold increase over the previously reported yields.


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Date of Award



Te Herenga Waka—Victoria University of Wellington

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Degree Grantor

Te Herenga Waka—Victoria University of Wellington

Degree Level


Degree Name

Doctor of Philosophy

Victoria University of Wellington Item Type

Awarded Doctoral Thesis



Victoria University of Wellington School

School of Chemical and Physical Sciences


Halton, B