Arylstannanes electrophilic substitution

The arylstannanes undergo electrophilic substitution more readily than do the parent protic compounds, through a similar Wheland intermediate (Equation (52)). 

Trialkyltin substituents are also powerful ipso-directing groups. The overall electronic effects are similar to those in silanes, but the tin substituent is a better electron donor. The electron density at carbon is increased, as is the stabilization of /S-carbocation character. Acidic cleavage of arylstannanes is formulated as an electrophilic aromatic substitution proceeding through an ipso-oriented c-complex. ... 

All three elements are susceptible to ipso replacement by electrophiles - such reactions have been studied extensively for arylsilanes and arylstannanes, where they occur via an electrophilic addition/silicon elimination mechanism analogous to other aromatic substitutions, but at a much faster rate than the corresponding replacement of hydrogen." Ipso substitutions also take place on heterocycles and, in the case of electron-rich systems, probably via the same type of mechanism. 

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