1.3- Dithietanes ring opening

Without additional reagents 1,3-Dithietane ring opening... 

Dicyanomethylene-l,3-dithietane rings open with nucleophiles with retention of both sulfur atoms and, while NaH produces hydrogen, the anion does not alkylate (Scheme 46) (64JOC497). 

The 4-methylene-l,3-dithietane-2-ones lose carbon oxysulfide to give thio-ketenes that dimerize to 2,4-dimethylene-l,3-dithietanes, as exemplified by the flash-vacuum thermolysis of 551. Reaction of several methylene 1,3-dithietane-2-ones with secondary amines also appears to proceed via loss of carbon oxysulfide followed by addition of the amine to the thioketene. An exception to the loss of carbon oxysulfide is the reaction of a guanidine derivative with 551 to give the ring-opened product 552. ... 

The most common reaction of 2,4-bis-(methylene)-l,3-dithietanes with nucleophiles involves an apparent Michael addition to an electron-deficient double bond followed by ring-opening. Further reactions may ensue depending on the functional groups present. The reactions of 578 have been extensively investigated. Reactions have been reported with ethoxide ion and thiolate ions, ammonia and amines " " - (e.g., the formation of 579), hydra-... 

Ring-opening of 2,2,4,4-tetrakis(trifluoromethyl)-l,3-dithietan occurs on treatment with potassium fluoride, hexafluoropropene, and cuprous bromide, or with potassium fluoride, alcohols, and copper(i) or silver salts. Treatment of the desaurin (80) with o-amino-phenols gives oxazepine derivatives, and with o-phenylenediamines, diazepines. ... 

Various ring-opened products are obtained from desaurins and nucleophiles (amines, mercaptides, hydrazine). Several thioketens are formed in the loss of carbonyl sulphide from 4-dialkylidene-l,3-dithietan-2-ones. ... 

A one-pot synthesis of alkyl perfluoroalkyl ketones has been developed. Phosphoranes, generated in situ, are acylated with a perfluoroacyl anhydride, and the resulting phosphonium salts are hydrolyzed with alkali [48] (equation 48) Hydrolysis of a carbon-sulfur bond in 2-chloro-2,4,4-trifluoro-1,3-dithietane-S-trioxide, which can be obtained from 2,2,4,4-tetrachloro-l,3-dithietane by fluor-ination with antimony trifluonde followed by selective oxidauons, opens the ring to produce 2-chloro-l,l,2-trifluorodimethyl sulfone [49] (equation 49)... 

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