Synthesis and Thermal Stability of 3-Substituted 3-Benzostibepines

Fully unsaturated 3-benzostibepines having various aryl groups on antimony have been prepared by a ring closure reaction of an appropriate antimony dihalide (ArSbBr(2)) with (Z,Z)-1,2-bis(2-lithiovinyl)benzene generated by treatment of (Z,Z)-1,2-bis(2-bromovinyl)benzene with t-BuLi. All the stibepines obtained here are thermolabile in solution toward heteroatom extrusion. The half-lives of the stibepines estimated from (1)H NMR spectral analysis revealed that the thermal stabilities of the stibepines bearing a heteroatom moiety (N, O) in the vicinity of the antimony are far less stable than others.