Dithiolanium ylide

Vedejs and co-workers have developed a clever method for generation of monothiooxalate derivatives by the dithiolanium ylide cycloreversion shown in Eq. (10).26... 

N-phenylmaleimide. The formation of 2-phenacylidene-3-methyl-5-phenyl-l,3-oxazoline by the treatment of the salt (158) with sodium hydride in DMSO was considered to proceed through the thiocarbonyl ylide (159). However, the thiocarbonyl ylide (160), which in a similar manner to that mentioned above was generated from its corresponding dithiolanium salt, instead underwent a spontaneous ring-closure, yielding the spiro-compound (161). The thiocarbonyl ylide dipolar characteristics of phenyl-substituted thieno[3,4-c]pyrroles, phenyl-substituted thieno[3,4-c]thiophens, and the thieno[3,4-/)benzo[c]thiophen (162) have been substantiated by their reactions with dipolarophiles. The first representative (164) of the hitherto... 

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