Synthesis of novel five‐ and six‐membered heteroaromatic sulfonyl fluorides bearing bromine atom at various positions of the heterocyclic ring is described. The synthetic utility of these compounds is demonstrated by the Suzuki, Stille, and Negishi cross‐coupling reactions, which proceeded chemoselectively at the aryl bromide moiety with 69–98 % yields. The tolerance of the SO2F group towards the coupling reaction conditions was confirmed in most of the experiments. The proposed method was efficient for either sp2–sp2 or sp2–sp3 C–C couplings. The developed procedure provides rapid access to various substituted heterocyclic sulfonyl fluorides.
One‐pot intramolecular cyclization of novel sp3‐enriched cyanoalkylsulfonyl fluorides into spirocyclic β‐ or γ‐sultams is disclosed. The method relies on nitrile group reduction followed by sulfonylation of amino group thus formed upon mild conditions (NaBH4, NiCl2·6H2O in MeOH). Cyclization proceeds smoothly with considerable efficiency (48–84 %, 10 examples) on up to 30 g scale. The cyanoalkylsulfonyl fluoride intermediates can be obtained via S‐nucleophilic substitution in β‐functionalized alkanenitriles or double alkylation of α‐alkylthioacetonitrile, followed by oxidative chlorination with Cl2 and further reaction with KHF2. The title mono‐ and bifunctional sultams are advanced sp3‐enriched building blocks for drug discovery and organic synthesis providing novel substitution patterns and frameworks mimicking saturated nitrogen heterocycles such as pyrrolidine/pyrrolidone.
o-Bromoarylsulfonylated amidines prepared either by acylation of amidine with o-bromoarylsulfonyl chloride or through the reaction of o-bromoarylsulfoamide with lactime ether underwent Cu(I)-catalyzed intramolecular cyclization to give 4H-1,2,4-benzothiadiazine-1,1-dioxides in good yield. By varying substituents on arylsulfonyl moieties, amidines, and lactime ethers, a small library of structurally diverse 4H-1,2,4-benzothiadiazine-1,1-dioxide derivatives was prepared.
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