Thiocarbonyl ylides heteroatoms

Thiocarbonyl ylides (1) belong to tbe family of sulfur-centered 1,3-dipoles cbaracterized by tbe presence of two sp C atoms attached to tbe sulfur atom. Formal replacement of one of the C atoms by heteroatoms such as NR3, O, and S lead to the other representatives of the family, namely, thiocarbonyl S-imides (2), S-oxides (sulfines) (3), and S-sulfides (thiosulfines) (4), respectively. 

The following types of dipolarophiles have been used successfully to synthesize five-membered heterocycles containing three heteroatoms by [3 + 2]-cycloaddition of thiocarbonyl ylides azo compounds, nitroso compounds, sulfur dioxide, and Al-sulfiny-lamines. As was reported by Huisgen and co-workers (91), azodicarboxylates were noted to be superior dipolarophiles in reactions with thiocarbonyl ylides. Differently substituted l,3,4-thiadiazolidine-3,4-dicarboxylates of type 132 have been prepared using aromatic and aliphatic thioketone (5)-methylides (172). Bicyclic products (133) were also obtained using A-phenyl l,2,4-triazoline-3,5-dione (173,174). 

In our opinion, heterofullerenes with divalent heteroatoms, like O and S, are potentially interesting compounds because they could possibly exist as neutral ylide structures with > C-0+< and > C-S+< bonds, respectively. Alternative structures for C59O and C59S are less ionic truncated quasi-fullerene structures bearing a carbonyl or thiocarbonyl moiety, as shown in Fig. 35. 

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