School of Chemistry, University of Hyderabad, Hyderabad 500 046, Telangana, India.
Org Biomol Chem. 2019 Jul 17;17(28):6880-6894. doi: 10.1039/c9ob00994a.
An efficient Cu(i)-catalysed cyclisation reaction of 2-iodobenzene sulfonamides with aryl-isothiocyanates and isocyanates that affords functionalised benzodithiazines and benzothiadiazinones, respectively, has been developed. Thus, in the reaction with aryl isothiocyanates (Ar-N[double bond, length as m-dash]C[double bond, length as m-dash]S), the C[double bond, length as m-dash]S moiety participates in the cyclisation leading to a dithiazine. By contrast, in the case of aryl isocyanates (Ar-N[double bond, length as m-dash]C[double bond, length as m-dash]O), the N[double bond, length as m-dash]C part is involved in the cyclisation and a thiadiazinone is obtained. Analogous reactions of isothiocyanates with N-tosyl-2-iodo-anilines and 2-iodo-benzyl sulfonamides afford (benzothiazin-2-ylidene)anilines and (benzothiazol-2-ylidene)anilines, respectively. Probable mechanistic pathways are briefly discussed.
一种高效的 Cu(i)-催化的 2-碘苯磺酰胺与芳基异硫氰酸酯和异氰酸酯的环化反应，分别得到功能化的苯并二噻嗪和苯并噻二嗪酮。因此，在与芳基异硫氰酸酯（Ar-N[双键，长度为 m-dash]C[双键，长度为 m-dash]S）的反应中，C[双键，长度为 m-dash]S 部分参与环化反应，生成二噻嗪。相比之下，在芳基异氰酸酯（Ar-N[双键，长度为 m-dash]C[双键，长度为 m-dash]O）的情况下，N[双键，长度为 m-dash]C 部分参与环化反应，得到噻二嗪酮。类似的异硫氰酸酯与 N-甲苯磺酰基-2-碘苯胺和 2-碘苯甲磺酰胺的反应分别得到（苯并噻嗪-2-亚基）苯胺和（苯并噻唑-2-亚基）苯胺。简要讨论了可能的反应机理。
