Sulfonylative and Azidosulfonylative Cyclizations by Visible‐Light‐Photosensitization of Sulfonyl Azides in THF
نویسندگان
چکیده
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.
منابع مشابه
Synthesis of N-Sulfonyl Amidines and Acyl Sulfonyl Ureas from Sulfonyl Azides, Carbon Monoxide, and Amides.
A Pd-catalyzed and ligand-free carbonylation/cycloaddition/decarboxylation cascade synthesis of sulfonyl amidines from sulfonyl azides and substituted amides at low CO pressure is reported. The reaction proceeds via an initial Pd-catalyzed carbonylative generation of sulfonyl isocyanates from sulfonyl azides, followed by a [2 + 2] cycloaddition with amides and subsequent decarboxylation, which ...
متن کاملSelective formation of 1,5-substituted sulfonyl triazoles using acetylides and sulfonyl azides.
The reaction of acetylides with sulfonyl azides was found to selectively form 1,5-substituted sulfonyl triazoles. This reaction thus provides access to the regioisomeric product as compared to the popular copper-catalyzed azide-alkyne cycloaddition. The reaction is efficient and selective with a variety of alkyne sources and sulfonyl azides and can incorporate an additional electrophile to yiel...
متن کاملCopper(i)-catalyzed sulfonylative Suzuki-Miyaura cross-coupling.
Using a simple copper(i) catalyst has allowed a high yielding sulfonylative-Suzuki-Miyaura cross-coupling reaction to be developed. The process provides a single step route to diaryl sulfones from the direct combination of aryl boronic acids, sulfur dioxide and aryl iodides, and represents the first sulfonylative variant of a classic cross-coupling reaction. Sulfur dioxide is delivered from the...
متن کاملN-Sulfonylketenimines as Useful Synthons in a Novel Synthesis of Functionalized 2-Oxoindoline Derivatives
The synthesis of a novel class of 2-oxoindolin-3-ylidene-(1-arylhydrazinyl)-2-aryl(alkyl)ethylidene derivativesvia a copper-catalyzed tandem reaction of isatin, arylhydrazines, sulfonyl azides and terminal alkynes is described.
متن کاملTermination of Mn(III)-based oxidative cyclizations by trapping with azide.
The radicals formed in Mn(III)-based oxidative free-radical cyclizations of beta-keto esters and malonate esters can be trapped with sodium azide and Mn(III) to give cyclic and bicyclic azides in 30-80% yield. Reduction of the azide gives bi- and tricyclic lactams. [reaction: see text]
متن کامل