Heterocyclic pentafluorophenyl sulfonate esters as shelf stable alternatives to sulfonyl chlorides

Ring Opening of Pymisyl‐Protected Aziridines with Organocuprates

“…These sulfonyl chlorides have limited stability and can be substituted by the much more stable pentafluorophenyl sulfonate esters. [15] Attempts to use triethylamine or solid potassium carbonate in dichloromethane in the synthesis of 7 and 8 gave low yields of the N-sulfonylated aziridines, accompanied by byproducts formed by chloride ion ring opening of the aziridine; which is a testimony to the high propensity of sulfonyl-activated aziridines to react with nucleophiles.…”

“…An initial survey of the literature indicated that the benzothiazole‐2‐sulfonyl group (Bts), introduced by Vedejs et al., would be a likely candidate as a replacement for Ns in organometallic reactions 14. The Bts group can easily be introduced by using the corresponding sulfonyl chloride or pentafluorophenyl sulfonate ester,15 and Bts‐protected amines have been used as nucleophiles in the Mitsunobu reaction;16 the Bts group can be removed with a thiol in analogy to the Ns group 17. Furthermore, the Bts group has been shown to be stable under a range of different reaction conditions 18…”

“…The sulfonyl‐protected aziridines 7 and 8 were prepared by adding 1,3,4‐thiadiazole‐2‐sulfonyl chloride (ThsCl) or pyrimidine‐2‐sulfonyl chloride (pymisyl chloride; generated in situ) to 2‐methylaziridine in a two‐phase mixture of ethyl acetate and aqueous potassium carbonate (Scheme ). These sulfonyl chlorides have limited stability and can be substituted by the much more stable pentafluorophenyl sulfonate esters 15…”

Synthesis of Aryl Sulfonamides via Palladium-Catalyzed Chlorosulfonylation of Arylboronic Acids

“…Upon examining the reaction sequence from a retrosynthetic perspective, we envisioned exploiting arylsulfonate esters ( 3 , Scheme 1) 14 as the immediate precursors to sulfonamides, and thus potential targets for Suzuki-Miyaura cross-coupling. In turn, we proposed that sulfonate esters ( 3 ) could be prepared from an aryl chlorosulfate derivative ( 2 ) 15 via Pd-catalysis.…”

Synthesis of Heteroaryl Sulfonamides from Organozinc Reagents and 2,4,6-Trichlorophenyl Chlorosulfate

“…Although examples of aryl sulfonate esters as shelf-stable alternatives to thermally unstable heterocyclic sulfonyl chlorides have been reported, these compounds are still prepared by using the unstable sulfonyl chlorides in question (Figure 1 ). 11 …”