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

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,S′ ‐trioxides 12a/b , which are formed from the oxathiirene S ‐oxides 9a / b . The latter compounds bear the characteristics of masked carbenes (τ estimated as 700 ps) and are quenched by methanol and cyclooctene. Singlet disulfonylcarbenes 2a/b are not predicted to be minima, since all attempts at optimizing the geometry of 2a led to 9a instead. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)