Synthesis of alkenyl sulphoxides by intramolecular and intermolecular addition of sulphenic acids to alkynes

Abstract

Alkyne-a-sulphenic acids formed by thermolysis of w-(t-butylsu1phinyl)alkynes at 140 "C cyclized regiospecifically to 2-methylenethiacycloalkane 1 -oxides ; 2-methylenethietan 1 -oxide was not formed in this way. 2-Methylpropane-2-sulphenic acid, obtained by heating di-t-butyl sulphoxide, added regioselectively to oct-1 -yne to give predominantly 2-t-butylsulphinyloct-1 -ene, which itself decomposed thermally to a mixture of dioctenyl sulphoxides by way of alkenesulphenic acid-dialkyl sulphine interconversions. Benzenesulphenic acid, methanesulphenic acid, and ethoxycarbonylmethanesulphenic acid, conveniently generated by thermolysis of 1 -cyano-2alkyl(or aryl)sulphinylethanes, underwent intermolecular addition to unactivated and activated alkynes regioselectively to give alkenyl sulphoxides in good yields.University, Sheffield S3 7HF

One-pot Synthesis of Aryl Sulfones from Alcohols

“…These groups proved to be compatible under the reaction conditions to afford the corresponding sulfones 2n, 27 2o, 28 and 2p. 29 In most cases, the yields of the sulfones from nonactivated alcohols were slightly lower than those of allylic sulfones.…”

Sulfinyl Homo- and Hetero-Dienes from Sulfenic Acids: An Approach Towards Six-membered Nitrogen Heterocycles in Enantiomerically Pure Form

“…3-[(1S)-Isoborneol-10-sulfinyl]propanenitriles (sulfur epimeric mixture 9) 2 were choosen as suitable precursors of sulfenic acid 10 which was obtained by their thermolysis in toluene (Scheme 3). Isoborneolsulfenic acid 10 was generated in situ and reacted, (i) with 2-butynal dimethylhydrazone (11), prepared from crotonaldehyde following the literature procedure, 10 and (ii) with a 60:40 mixture of (E)-and (Z)-3-phenyl-2-propynal dimethylhydrazones (12) and (13). 11 Compounds 12 and 13 were prepared from phenylpropargyl aldehyde (14) and 1,1-dimethylhydrazine and are separable by column chromatography.…”

“…A complete regioselectivity was observed in this reaction, in favour of 2-sulfinyl-3,3diethoxypropenes. 12…”

“…Found: C, 68.70; H, 7.25. (R S ,E,E)-3-[(1S)-Isoborneol-10-sulfinyl]-3-phenyl-2-propenalDimethylhydrazone (Sulfoxide which is reported above as a product of the addition of sulfenic acid 10 to (E)-3-phenyl-2-propynal dimethylhydrazone(12), was prepared in very good yield by adding dropwise a solution of 1,1-dimethylhydrazine (0.15 g, 2.5 mmol) in Et 2 O (2 mL) to a solution of (R S ,E)-3-[(1S)-isoborneol-10-sulfinyl]-3-phenyl-2-propenal (17) (0.70 g, 2.1 mmol) in Et 2 O (10 mL) at 0 °C. After allowing the solution to warm to r.t., water (5 mL) was added, the crude mixture was extracted with Et 2 O (3 × 10 mL), and the organic layers collected and dried over Na 2 SO 4 .…”

Sulfoxides as an intramolecular sulfenylating agent for indoles and diverse applications of the sulfide-sulfoxide redox cycle in organic chemistry

“…Formation of sulfenic acids from sulfoxides and their sulfenylation of a nucleophilic nitrogen atom (to prepare a series of benzoisothiazolones) has been reported 39 to occur under nearly the same conditions reported here (trichloroacetic anhydride/pyridine or refluxing toluene/pyridine). Glucosulfinylpropanenitriles 40 as well as t-butyl alkyl sulfoxides, 41 upon heating in an inert solvent, generate transient sulfenic acids which have been trapped using methyl propiolate or other alkynes.…”