Abstract
The generation of sulfonyl radicals from sulfonyl azides using visible light and a photoactive iridium complex in THF is described. This process was used to promote sulfonylative and azidosulfonylative cyclizations of enynes to give several classes of highly functionalized heterocycles. The use of THF as the solvent is critical for successful reactions. The proposed mechanism of radical initiation involves the photosensitized formation of a triplet sulfonyl nitrene, which abstracts a hydrogen atom from THF to give a tetrahydrofuran‐2‐yl radical, which then reacts with the sulfonyl azide to generate the sulfonyl radical.
Highlights
Azides are highly versatile functional groups because they undergo many different reactions.[1,2] The recent, dramatic increase in the use of visible light photocatalysis in synthesis[3] has led to its application in reactions of organic azides, resulting in several interesting new processes.[4]
We have described sulfonylative and azidosulfonylative cyclizations of enynes that give several classes of highly functionalized heterocycles
These reactions operate through radical chain mechanisms, with the combination of sulfonyl azide, THF, visible light, and a photoactive iridium complex serving as a “smart initiation”[11a] system for the generation of sulfonyl radicals
Summary
Azides are highly versatile functional groups because they undergo many different reactions.[1,2] The recent, dramatic increase in the use of visible light photocatalysis in synthesis[3] has led to its application in reactions of organic azides, resulting in several interesting new processes.[4]. We describe radical cyclizations of enynes which use sulfonyl azides, visible light, and a photoactive iridium complex to give several classes of highly functionalized oxacycles and azacycles (Scheme 1B). The products can contain the azide group, a useful handle for further derivatizations.[1,2]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
