REACTION OF A STANNYLENE WITH CARBON-DISULFIDE - FORMATION OF A NOVELTIN-CONTAINING 1,3-DIPOLE AND ITS REACTIVITY

The reaction of the stannylene Tbt(Tip)Sn: (1; Tbt = 2,4,6-tris[bis(tr imethylsilyl)methyl]phenyl, Tip = 2,4,6-triisopropylphenyl), synthesiz ed by reduction of Tbt(Tip)SnBr2 with lithium naphthalenide, with carb on disulfide in the presence of electron-deficient olefins, such as me thyl acrylate, acrylonitrile, and methyl methacrylate, gave cycloadduc ts of the intermediary 1,3-dipole Tbt(TipSn--S-C+=S (4). In the absenc e of the olefins, there was formed the unsymmetrical olefin Tbt(Tip)-S nS2C=CS2C(=S)SSnTbt(Tip) (8), the structure for which was established by X-ray crystallography. Upon thermolysis, the olefin 8 underwent CS2 extrusion to afford the symmetrical olefin Tbt(Tip)SnS2C=CS(2)SnTbt-( Tip) (9). The intermediary 1,3-dipole 4 showed lambda(max) at 608 nm a nd was stable up to ca. -30 degrees C.