Investigation into the Organobismuth Dismutation and Its Use for Rational Synthesis of Heteroleptic Triarylbismuthanes, Ar12Ar2 Bi

Organobismuthanes undergo dismutation, a substituent scrambling process, complicating the synthesis of unsymmetrically trisubstituted bismuthanes of the general formula (Ar2ArBi)-Ar-1-Bi-2. Although the dismutation is a mechanistically diverse phenomenon, at ambient or lower temperatures, dismutation is triggered mainly by an electrophilic bismuth source. Therefore, the selection of the electrophile, (Ar2BiX)-Bi-1 (X = tosylate or iodide if Ar-1 = mesityl) or (ArBiX2)-Bi-1(X = tosylate), and its use in low concentration during the reaction is key to suppressing the dismutation, leading to new, streamlined protocols utilizing direct arylations of (Ar2BiX)-Bi-1 (X = OTs or I) or (ArBi)-Bi-1(OTs)(2) with organozincs affording heteroleptic triarylbismuthane (Ar2ArBi)-Ar-1-Bi-2.