Osei-Kissi, Daniel Kwasi; (1993) Preparation, properties and reactions of organotin hydrides. Doctoral thesis (Ph.D), UCL (University College London).

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Abstract

Trialkyltin hydrides, particularly tributyltin hydride are familiar reagents with an established place in organic synthesis, but little work has been carried out on the properties and applications of other tin hydrides. This thesis reports a study of the reaction of tributyl and triphenyltin hydrides with a variety of alkynes at, or above, 80[degrees]C in the presence of a radical initiator to give the corresponding vinyltin compounds. The characteristic NMR spectra are used to define the regio- and stereo- selectivity of the reactants. A series of dibutyltin hydrides, Bu2SnXH, have been prepared by disproportionation between Bu2SnH2 and Bu2SnX2, where X = Cl, OCOCH3, OCOCF2CI, OCOC6H5. At room temperature these compounds Bu2SnXH evolve hydrogen with formation of the corresponding distannanes XBu2SnSnBu2X and the mechanism of these reactions has been shown to be a radical chain process, involving, we believe, homolytic substitution of a tin radical at a tin centre with the displacement of a hydrogen atom. These hydrides, Bu2SnXH, are then shown to bring about hydrostannation and hydrostannolysis reactions at or below room temperature in the absence of an initiator. It is suggested that the spontaneous homolytic decomposition initiates the familiar radical reactions with the substrates. The regio- and stereo- selectivities of the reactions are deduced from the NMR spectra and compared with those of the corresponding trialkyltin hydrides. These reactions, which occur readily under very mild conditions, have some potential applications in organic synthesis.

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