Lewis Acid Chelation of [NR]<sup>2-</sup> by 2,2‘-Diborabiphenyl:  9,11-Diboratacarbazole Heterocycles

A new heterocyclic framework, the dianionic 9,11-diboratacarbazole, has been prepared from a bis(trimethylphosphine)-stabilized 2,2‘-diborabiphenyl derivative, <b>1</b>, and H<sub>2</sub>NR (R = Ph, CH<sub>2</sub>C<sub>6</sub>H<sub>4</sub>-<i>p</i>-OMe). The heterocyclic framework is formally assembled via Lewis acid chelation of the [NR]<sup>2-</sup> dianion by 2,2‘-diborabiphenyl. These dianions are isoelectronic with the well-studied fluorenyl monoanion.