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Title: A silicon controlled Ireland-Claisen rearrangement as a stereoelectronic probe
Author: Betson, M. S.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2002
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The work described in this thesis concerns the study of two general types of silicon-controlled Ireland-Claisen rearrangements, 152 and 155. We propose that the transition states for these two rearrangements are sterically very similar, but the flow of electron density is in opposite directions for the two cases. Any significant difference in the diastereoselectivities of the two rearrangements can therefore be ascribed to the difference in electronic nature of the transition states. Our studies showed that both classes of rearrangement gave the anti products with good to excellent selectivity. This silicon-controlled rearrangement was taken one step further and used to control the formation of three contiguous stereocentres (e.g. 306(r)307+308). The last part of this thesis describes the study of some silicon-controlled nucleophilic additions to the acyclic substrates 230, 354 and 355. The addition to 230 showed surprisingly little selectivity, whereas additions to 354 and 355 were well controlled, but the trapping of the resultant enolates was not.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available