SECONDARY REACTIONS OF SULFENES FROM SULFONYL CHLORIDES AND TERTIARY-AMINES .2. FORMATION OF EPISULFONES, SULFONYLSULFENE AMINE S,N-ADDUCTS, AND CHLOROSULFINES FROM PRIMARY SULFONYL CHLORIDES AND TERTIARY-AMINES

Secondary Reactions of Sulfenes from Sulfonyl Chlorides and Tertiary Amines, 2. — Formation of Episulfones, Sulfonylsulfene — Amine S.N‐Adducts. and Chlorosulfines from Primary Sulfonyl Chlorides and Tertiary Amines The reaction of primary sulfonyl chlorides 1b–m with the tertiary amine bases quinuclidine, DABCO, Me3N, Et3N, Bu3N, EtiPr2N, and 1,2,2,6,6‐pentamethylpiperidine is studied in acetonitrile solution between − 40 and 80°C. The 2,3‐dialkylthiirane 1,1‐dioxides 4 (trans/cis > 1) and the alkenes 5 [(E)/(Z) > 1] are obtained in high yields with Et3N at − 40°C. The stereochemistry is influenced by the amine base B in the ring closure reaction and partially by epimerization of the episulfones 4. Hindered bases favor the cis, β‐branched sulfonyl chlorides the trans isomer. Competing formation of the sulfonylsulfene–amine S,N‐adducts 7 is only observed with quinuclidine, DABCO, and Me3N, which are also the most active amines in the epimerization of the cis‐2,3‐diarylthiirane 1,1‐dioxides 4. Methanesulfonyl chloride (1a) yields the mesylsulfene–amine S,N‐adducts 7a with Me3N and Et3N in MeCN, but thiirane 1,1‐dioxide (4a) with EtiPr2N in MeCN or with Et3N in Et2O. Formation of chlorosulfines 10 is favored by higher temperature (T > 20°C), hindered amine bases and β‐branched sulfonyl chlorides. Isolation of 10g and 10h in high yields shows that tert‐alkylchlorosulfines are rather stable sulfines. Copyright © 1990 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim