Synthesis and Structures of Two Isomeric 4‐Diazo‐2,3,4,5‐tetrahydrofuran‐3‐ones

The two regioisomeric 4‐diazo‐2,3,4,5‐tetrahydrofuran‐3‐ones 6 and 7 were prepared via the common intermediate 2,3,4,5‐tetrahydro‐2,2‐dimethyl‐5,5‐diphenylfuran‐3‐one ( 8 ). Diazo transfer with 2,4,6‐triisopropylbenzenesulfonyl azide yielded 6 , whereas 7 was obtained via oxidation of the monohydrazone 12 , which was prepared selectively from tetrahydrofuran‐3,4‐dione 11 . The crystal structures of 6 and 7 have been established by X‐ray crystallography.     

New Photochemical Reaction in the Series of Diazofuranones

Russian Journal of Organic Chemistry -     

Photochemical Reactions of Regioisomeric 2,2‐Dimethyl‐5,5‐diphenyl‐ and 5,5‐Dimethyl‐2,2‐diphenyl‐Substituted Diazo Ketones of a Tetrahydrofuran Series

The principal direction of conventional photolysis of the regioisomeric 2,2‐dimethyl‐5,5‐diphenyl‐ and 5,5‐dimethyl‐2,2‐diphenyl‐substituted 4‐diazodihydrofuran‐3(2H)‐ones 1a and 1b , respectively, is the Wolff rearrangement, while other photochemical processes, which are giving rise to the formation of C? H‐insertion, 1,2‐alkyl‐ or ‐aryl‐shifts, as well as H‐atom‐abstraction products occur to a much lower degree (Schemes 2 and 3). The ratio of similar reaction products from both regioisomers 1a and 1b is essentially independent of their structure, and a substantial effect of the relative position of the Ph and diazo group to each other on the yield of C? H‐insertion products does not occur. Based on stereochemical considerations, the Wolff rearrangement of diazodihydrofuran‐3(2H)‐ones apparently proceeds in a concerted manner, whereas the appearance in the reaction mixture of 1,2‐shift and H‐atom‐abstraction products points to the parallel generation during photolysis of singlet and triplet carbenes (Schemes 4 and 5).     

Fluorescent signaling based on sulfoxide profluorophores: application to the visual detection of the explosive TATP

The first visual fluorescence-based assay for the peroxide explosive triacetone triperoxide (TATP) is described. The assay is based on a conceptually new fluorescence signaling mechanism, in which nonemissive pyrenyl sulfoxide profluorophores are oxidized to visibly emissive pyrenyl sulfones. Although not without limitations, these first-generation fluorescent probes can provide a visual response to ca. 100 nmol of TATP. In addition, the success of this assay suggests the potential for broader application of aryl sulfoxides in fluorescent chemosensing.