Pericyclic and related rearrangements for the synthesis of nitrogen heterocyclic ring systems

Thesis

The thesis describes synthesis and reactions of allene azides tethered to various functional groups and the application of the discovered cascade transformations towards the synthesis of radianspene J model system.

Chapter 1 covers reactions of simple allene azides containing alkyl and cycloalkyl substituents. Thermal rearrangements of these substrates delivered isocyanides and azadienes via the proposed azatrimethylenemethane (ATMM) intermediates.

On the other hand, vinylidenecyclopropanes (VDCPs) gave dramatically different products, as described in Chapter 2. A phenyl-substituted VDCP was transformed into an unstable polycyclic compound by a divinylcyclopropane rearrangement. Chapter 3 discusses allene azides tethered to furan, N-substituted pyrroles, and E- and Z-dienes. Depending on the structure of the starting material, products of formal (3+4)- or (2+3)-cycloaddition were formed.

Finally, an application of the discovered cyclisation cascade towards total synthesis is described in Chapter 4. A model system of radianspene J was assembled using a key transannular cycloaddition of a macrocyclic allene.

Authors: Zhurakovskyi, O

• Publication date: 2013
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: Oxford University, UK
• Language: English
• Keywords: total synthesis; pericyclic reactions; azides; allenes; rearrangement; cycloadditions; azatrimethylenemethane; ene reaction; Radianspene J
• Subjects: Heterocyclic chemistry; Organic synthesis; Organic chemistry; Natural products