Reagentless photochemical transformations of dihydrofuropyridinones to azocines

Abstract

Herein, the thermal and photochemical reactions of dihydrofuropyridinones will be described. Thermal rearrangements of alkynylcyclobutenones are well established routes to benzoquinones, cyclopentediones and furanones; all of which are found in several natural products. Recently, the Harrowven group reported a short synthesis of dihydrofuropyridinones via the reagentless thermolysis of alkynylcyclobutenones. Following less successful thermal reactions of dihydrofuropyridinones, we are pleased to report that their photochemical rearrangements were found to exclusively give 8‐membered nitrogen‐ containing rings, known as azocines. 8‐Membered rings are particularly difficult to synthesise; however, we report the synthesis of azocines in high yields without the need for high dilution or catalysis techniques. Azocines are found in many natural products and are highly desirable within medicinal chemistry. Optimisation of the photochemical rearrangement and the photochemical set up will be detailed in this thesis. A library of 22 azocines with various substituents has been created, including the addition of heterocycles and non‐aromatic groups. Finally, both the thermal and photochemical processes were linked under continuous flow to give a reagentless daisy chain sequence to azocines. This joint venture with Dr. Wei Sun resulted in higher yields of the azocines when compared to the step‐wise procedures.

More information

Identifiers

ORCID for David Harrowven: orcid.org/0000-0001-6730-3573

Catalogue record

Export record