Synthesis and Structure of Pentaorganostannate Having Five Carbon Substituents

The reaction of spirostannabifluorene with methyllithium gave lithium pentaorganostannate, which is an intermediate of the transmetalation reaction on the tin atom and the first example of a stable pentaorganostannate having five carbon substituents. The X-ray structural analysis reveals its slightly distorted trigonal bipyramidal structure, the apical bonds of which have a considerable s character. The unique structure of the lithium pentaorganostannate is also discussed by the aid of theoretical calculations.