Versatile Reactivity of Stannene Tip₂SnCR₂ with Unsaturated Compounds

The stannene Tip2SnCR2 (1; Tip = 2,4,6-triisopropylphenyl, CR2 = 2,7-di-tert-butylfluorenylidene) gives [2 + 2] cycloadditions with phenyl isocyanate and diphenylketene (by the CO bond) and phenyl isothiocyanate (by the CS bond) to afford the corresponding four-membered heterocycles. [2 + 3] cycloadditions are observed between 1 and N-tert-butyl α-phenyl nitrone and methyl (benzylideneamino)­acetate. Very different reactions occur with nitriles: an insertion of a C–H bond of acetonitrile across the SnC double bond and a [2 + 2] cycloaddition between SnC double bond and CN unsaturation of pivalonitrile.