The synthesis of an electron deficient diene and progress towards the first total synthesis of jatrorrhizine

Swinamer, Alan (1997) The synthesis of an electron deficient diene and progress towards the first total synthesis of jatrorrhizine. Masters thesis, Memorial University of Newfoundland.

[English] PDF (Migrated (PDF/A Conversion) from original format: (application/pdf)) - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (21MB) [English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. (Original Version)

Abstract

The methodology for the synthesis of a new electron deficient 1,3-diene 44 was developed utilizing readily available starting materials. Generation of the diene was accomplished by introducing $\alpha,\beta$-unsaturation to an ester group via a sulfoxide elimination reaction. The diene itself polymerized readily, thus it was not isolated but was generated in situ in the presence of dienophiles with which the diene could react. The Diels-Alder properties of the diene have not as yet been studied but preliminary work on appropriate conditions for its generation was accomplished. This work suggested that the generation of the diene can be accomplished under sufficiently mild conditions that Diels-Alder reactions of the diene may occur before polymerization. Related work on similar electron deficient 1.3-dienes which are not generated in situ indicated that Diels-Alder reactions were occurring between these types of dienes and a variety of dienophiles, including electron rich, electron neutral and electron deficient dienes. -- A new approach to the first total synthesis of the protoberberine alkaloid, jatrorrhizine 154, was investigated using readily available starting materials. This convergent synthesis featured a Suzuki-type-biaryl cross-coupling reaction between a triflate 308 and a boronic acid 342 which proceeded in good yield. The present synthesis is the first known case of the synthesis of a protoberberine alkaloid using the biaryl cross-coupling methodology. The synthesis was accomplished on a small scale only as the isoquinolinol 318 was available in limited quantities. This synthesic route can be readily applied to the synthesis of other members of the protoberberine family of alkaloids, many of which have shown potential medicinal uses.

Actions (login required)

View Item