Towards the total syntheses of aspidospermidine and aspidofractinine: the curious chemistry of the indolinyl radical
This thesis is concerned with the total syntheses of the natural products aspidospermidine and aspidofractinine. These targets are noteworthy not only for the biological activity displayed within the class but also for their interesting molecular architecture. Herein, two routes towards the natural products are presented. Key features of the first route, a unified approach to both targets via the indolinyl radical, include the elegant construction of the core ABDE ring system, a mild lactam reduction and synthesis of the key cyclic imine. The second route features a highly efficient Stille coupling and a Wittig olefination. Attempts to effect a critical radical cyclisation reaction are also discussed. The chemistry of the C2 indolinyl radical is investigated, in particular the influence of the C3 indolinyl substitution upon the radical pathway followed. A discussion of the study and its findings is presented in Chapter 4. A review of synthetic approaches to these natural products since 2007 is presented in Chapter 1, in addition to details on their isolation, characterisation and biosynthesis, and an overview of their biological activity. Experimental procedures and characterisation data are provided in Chapter 6
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