K. Tamao et al., Stereochemical control of the reaction of chlorosilane with methyllithium by the addition of metal cyanide: Inversion by potassium cyanide and retention by copper(I) cyanide, SYNLETT, 2001, pp. 964-966
In the 1,4-dichlorotetrasilane derivative composed of disilane units bearin
g two pentamethylene tethers, the substitution of a chlorine atom on the si
licon atom by the methyl group during the reaction with methyllithium mainl
y proceeds with inversion of configuration of the silicon atoms, (1) the yi
eld being dramatically improved by the addition of potassium cyanide, and (
2) the stereochemistry being changed to retention of configuration by the a
ddition of copper(I) cyanide.