Reactions of a phosphavinyl Grignard reagent with main group mono-halide compounds

The reactions of a phosphavinyl Grignard reagent, [CyPC(But)MgCl(OEt2)] Cy=cyclohexyl, with a variety of main group 13, 14 and 16 mono-halide compounds have been investigated. When the Grignard reagent is reacted with bromocatecholborane the terminal phosphavinyl complex, [(C6H4O2)B{C(But)PCy}], is formed. Related terminal phosphavinyl tin and gallium complexes, [R3Sn{C(But)PCy}], R=Me or Bun and [IGa{C(But)PCy}2], have been prepared by similar routes. The reaction of the Grignard reagent with PhSeCl has afforded a new λ5,λ5-diphosphete, [{(But)CP(Cy)(SePh)}2], the mechanism of formation of which is discussed. The preparation of a phosphavinyl selenium compound, [(C8H4O2N)PC(But)(SePh)], is also described. All compounds have been spectroscopically characterised and several have been crystallographically authenticated.