Are phenylboranes susceptible to ipso or meta electrophilic aromatic substitution, i.e. what's the regioselectivity?
A SciFinder search turns up very little on this type of transformation.
Qui and coworkers run halogenations of phenyl boronate esters using N-halosuccinimide using gold(III) catalysis. The regioselectivity was essentially 1:1:1 for ortho:meta:para. When the reaction was carried out with other substituents as well, the other substituent's directing group preference dominated the regioselectivity. Gold(III)-Catalyzed Halogenation of Aromatic Boronates with N-Halosuccinimides
There is one other reaction in SciFinder that is relevant, however I don't have access to the full text (and it's in Russian, so I wouldn't be able to read it anyway). The substrate is a benzene ring substituted with a borane cluster. The reported regioselectivity is 80:20 for meta:para.
Electrophilic substitution in the benzene ring of 9-phenyl-o- and -m-carborane. Zakharkin, L. I. et al Zhurnal Organicheskoi Khimii, 23(8), 1691-5; 1987.
9-(N-pyridine)-11-I-7,8-dicarba-nido-undecaborate are susceptible to ipso substitution and have substitution I-atom on Cl-atom. Read
Rudakov D. A., Potkin V. I. Chlorination of 9-dimethylsulfonio-7,8-dicarba-nido-undecaborane and 9-(N-pyridine-)-11-iodo-7,8-dicarba-nido-undecaborane. pp. 69--72
Chlorination of 9-dimethylsulfonio-7,8-dicarba-nido-undecaborane and 11-iodo-9-(N-pyridine)-7,8-dicarba-nido-unde-caborane with chlorine in dichloromethane produces 6,11-dichloro-9-dimethylsulfonio-7,8-dicarba-nido-undecaborane and 11-chloro-6-iodo-9-(N-pyridine)-7,8-dicarba-nido-undecaborane in 20% and 44% yields, respectively.