Studies of α,β-unsaturated thione S-imides and S-oxides: The synthesis of β-aminovinylarylthione S-imides and S-oxides from the thiones

✍ Scribed by Takao Saito; Norihito Shibahara; Shinichi Motoki

• Publisher: Elsevier Science
• Year: 1983
• Tongue: French
• Weight: 205 KB
• Volume: 24
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)85918-3

✦ Synopsis

The synthesis and chemical properties of ylidenesulfimides (thione S-imides, X=S=N-), a novel type of thiocumulene, have recently been investigated! For example, fluorenethione S-tosylimides react not only as a 4s-system (1,3dipoles, enophiles) but also as a 28-system (dienophiles) in cycloaddition reactions. 2 On the other hand, thione S-oxides (sulfines, XZ=S=O) are well-known and have been thoroughly investigated.3 However, non-cyclic c,8-conjugated sulfines as well as a,$-unsaturated thione S-imides are very inaccessible compounds. To our knowledge there have been only few reports concerning these thiocumulenes, viz. the formation of 1 by singlet-oxygen oxidation of 2,5_dimethylthiophene in methanol 4 and the thermal ganeration of 2 from its dimer obtained by mCPBA oxida-tion of the corresponding thione dimer. 5 Periselectivity6 and site selectivity in the reaction of these a,8-conjugated thiocumulenes also constitute an attractive subject. This communication deals with the first synthesis of the monomeric B-aminovinylarylthione S-imides and S-oxides.