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Title: The synthesis of (+)-laurencin
Author: Burton, J. W.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 1997
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Abstract:
(+)-Laurencin 1.163 was isolated from Laurencia glandulifera in 1965 and its structure proven by X-ray crystallographic analysis. This dissertation details the total synthesis of (+)-laurencin in 27 steps from (R)-malic acid 2.19 using a Yamaguchi lactonisation and an intramolecular hydrosilation as the key steps. (Fig 13229a) Chapter 1 reviews both the methods of oxocane construction, reported since 1989 and the previous enantioselective syntheses of (+)-laurencin by the Murai, Overman and Palenzuela groups. Chapter 2 describes the synthesis of the lactone 2.15 via the Claisen rearrangement of the ketene-acetal 2.16. Enolate hydroxylation studies on the lactone 2.15 for the formation of 2.14 are also reported. Due to the difficulties encountered with this reaction an alternative lactonisation approach to 2.14 was developed which is reported in Chapter 3. (Fig 13229b) Elaboration of the hydroxy-lactone 2.14 into the diol 2.12 was achieved via a procedure involving Petasis olefination and intramolecular transition metal catalysed hydrosilation. Conversion of the primary hydroxyl group of 2.12 into a methyl group involved the use of organocuprate chemistry. These two topics are the subject of Chapter 4. The completion of the synthesis of (+)-laurencin 1.163 is set out in Chapter 5. Model methods for the introduction of the side-chain and the bromine atom are reported.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.597149  DOI: Not available
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