Episulfidation of trans‐Cyclooctene with an 1,2,4‐Oxadithiolane

Abstract

The dipolar cycloaddition of thiobenzophenone S‐oxide (1) and 2,2,4,4‐tetramethyl‐3‐thioxocyclobutanone (2) generates the labile 1,2,4‐oxadithiolane I, which in the presence of trans‐cyclooctene (3) affords trans‐episulfide (9). In this direct sulfur transfer, the oxathiirane II and/or the dithiirane IV, both derived from the 1,2,4‐oxadithiolane I, are proposed as elusive episulfidating agents. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

2,2,4,4-Tetramethylcyclobutane-1-one-3-thione

“…51 In this multi-step reaction, a sulfur-transfer leading to a thiocarbonyl S-sulfide is proposed as a key step. The formation of equimolar amounts of 2,2,4,4-tetramethylcyclobutane-1,3-dione (52) indicates that in this system 1 acts as a sulfur donor. In a three-component system containing 50, 1, and (E)-cyclooctene, an episulfidation of the strained alkene is observed.…”

5‐Morpholino‐1,2,3,4‐thiatriazole as a Sulfur‐Transfer Reagent in the Reactions with Thioketones

“…Thus, 1a as well as the benzaldimine act as S-acceptors, and a thiaziridine was proposed as the S-donor [19]. 7 The formation of the 1,2,4-trithiolane is the result of a [2+3]-cycloaddition of the respective thioketone and the in situ formed thiocarbonyl S-sulfide ('thiosulfine') [3]. In the reactions reported in the present paper, the thermolabile 5-morpholino-1,2,3,4-thiatriazole (7) acts as the S-donor.…”

“…The C,S-double bonds of thioketones are prone interceptors of sulfur, and thiocarbonyl S-sulfides ('thiosulfines') are believed to be formed as the reactive intermediates. They can be trapped efficiently with dipolarophiles, and in the case of the thiocarbonyl group, the [2+3]-cycloaddition leads to 1,2,4-trithiolanes [3][4][5][6][7]. In these sulfurtransfer reactions, strained three-membered sulfur heterocycles such as thiiranes [3], or in situ formed thiaziridines [4][5] or oxathiiranes [6] [7] are the sulfur donors.…”

“…They can be trapped efficiently with dipolarophiles, and in the case of the thiocarbonyl group, the [2+3]-cycloaddition leads to 1,2,4-trithiolanes [3][4][5][6][7]. In these sulfurtransfer reactions, strained three-membered sulfur heterocycles such as thiiranes [3], or in situ formed thiaziridines [4][5] or oxathiiranes [6] [7] are the sulfur donors. The appearance of thiaziridines as intermediates was proposed for the reactions of thiocarbonyl compounds with organic azides, which are initiated by the [2+3]-cycloaddition to give 2,5-dihydro-1,2,3,4-thiatriazoles, followed by extrusion of N 2 .…”

“…The thermal decomposition of 5-morpholino-1,2,3,4-thiatriazole (7), which leads to the extrusion of an active form of sulfur, in the presence of different thioketones is described. The interception of the S-atom by the C=S-bond leads to in situ formation of an elusive thiocarbonyl S-sulfide of type 5.…”