Synthesis studies towards daphlongeranine B

Thesis

This thesis describes the development of a synthetic route towards daphlongeranine B, an alkaloid isolated from the fruits of Daphniphyllum longeracemosum, by utilising an intramolecular Michael addition to form its unique tricyclic core.

Chapter 1 gives a general introduction to the family of Daphniphyllum alkaloids together with some recent examples, from the literature, illustrating some synthetic attempts towards structurally similar alkaloids. This chapter also features our retrosynthetic analysis of daphlongeranine B.

Chapter 2 details the synthesis of the model spirocyclic enone 72 which was the vital building block needed to investigate the key intramolecular Michael addition. This key reaction was then successfully validated and access to the unique tricyclic core 64 of daphlongeranine B was made possible.

Chapter 3 expands the scope of the key intramolecular Michael addition step. This chapter first describes a synthetic route to the β-substituted spirocyclic enone 112 and subsequently validates the key intramolecular Michael addition step to give the tricyclic core 138 of daphlongeranine B.

Chapter 4 details a synthetic route towards the spirocyclic fragment 141 by utilising a Baker's yeast reduction and a tandem addition/cyclisation reaction.

Authors: Kallstrom, JED

• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: daphlongeranine B; natural product synthesis
• Subjects: Natural products; Chemistry; Synthetic organic chemistry; Organic synthesis; Organic Chemistry