Laser Flash Photolysis of Disulfonyldiazomethanes: Partitioning between Hetero‐Wolff Rearrangement and Intramolecular Carbene Oxidation by a Sulfonyl Group

Abstract

Laser flash photolysis of bis(phenylsulfonyl)diazomethane (1a) and ditosyldiazomethane (1b) leads to the formation of sulfonylsulfenes 8a/8b (λ max = 310 nm). Non-first-order kinetics and non-linear Stern−Volmer behavior suggest the formation of another transient species also absorbing at λ = 310 nm. Based on the results of DFT calculations, these species are tentatively identified as dithiocarbonate S,S,SЈ-trioxides 12a/b, which are formed from the oxathiirene

Taming Hazardous Chemistry in Flow: The Continuous Processing of Diazo and Diazonium Compounds

“…The benefits of utilising flow processing in the scale up of the nucleophilic addition of diazoesters was recently demonstrated by the Wirth group (Scheme 6). [75] In this system 17 was generated by diazotisation of glycine ethyl ester (20), and used in a telescoped nucleophilic addition to provide a library of b-hydroxy-a-diazoesters (21). The substrate benzaldehyde (22) was processed on a 38 mmol scale to provide 6 g of a-diazoester 21 in two hours of continuous operation.…”

“…Diazoalkanes are important alkylating reagents, [1,2] while a-diazocarbonyls are important for their role in generating carbenes [3][4][5] and metal carbenoids, [1,[5][6][7][8][9][10][11][12][13][14][15][16] and also for providing access to reactive ketene and heteroanalogous intermediates by means of the Wolff rearrangement. [17][18][19][20][21][22] Diazo compounds are also important 1,3-dipoles for heterocycle-forming cycloaddition reactions. [23][24][25][26][27][28] The diazonium ion moiety is an important leaving group in Sandmeyer, [29][30][31] Meerwein, [32,33] Balz-Schiemann [34,35] and palladium-catalysed cross coupling [36][37][38] chemistry; it is also an essential reagent for the preparation of azo compounds, the backbone of the synthetic dye industry.…”

Taming tosyl azide: the development of a scalable continuous diazo transfer process

“…[1][2][3][4] The α-diazocarbonyl compounds produced by diazo transfer are an important class of versatile synthetic intermediates due to their ability to generate reactive carbenes, [5][6][7] carbenoids, [7][8][9][10][11][12][13][14][15][16][17][18][19][20] ketenes and other heteroanalogous intermediates. [21][22][23][24][25][26] Despite being routinely used in small scale α-diazocarbonyl synthesis, tosyl azide is not suitable for use at larger scales. Tosyl azide has an impact sensitivity of 50 kg·cm, and explosive thermal decomposition can initiate at 120 °C.…”

Hetero‐Wolff Rearrangement of an α‐Sulfinyl Carbene: Thermally Activated Intersystem Crossing of the Lowest Excited Triplet State of a Ground‐State Singlet Carbene

“…Rearrangements of the Wolff‐type are not limited to acyl carbenes but can also occur with heteroanalogous acyl carbenes such as sulfonyl carbenes R–C–SO 2 R′ derived from α‐diazo sulfones. They undergo a facile heteroanalogous Wolff rearrangement to yield highly reactive sulfenes 10. α‐Sulfinyl carbenes represent a similar class of carbenes, and a lone pair at the sulfoxide sulfur atom stabilises the singlet state of the carbene.…”