Regioselective Catalytic and Stepwise Routes to Bulky,Functional‐Group‐Appended,and Luminescent 1,2‐Azaborinines

The regioselective syntheses of 1,2‐azaborinines is achieved using an unsymmetrical iminoborane through both catalytic and stepwise modular routes. The 1,2‐azaborinine ring can be selectively functionalized in the 4‐ and/or 6‐position through control of the stepwise reaction sequence, allowing access to vinyl‐functionalized and redox‐active, luminescent, donor‐functionalized 1,2‐azaborinines. The electrochemistry and photochemistry of a tetraarylamine‐substituted 1,2‐azaborinine are studied. Cyclic voltammetry of this compound, relative to a non‐B,N‐substituted reference molecule, showed an additional oxidation wave assigned to the oxidation of the azaborinine ring, while emission spectroscopy indicated that the azaborinine was significantly more fluorescent than the reference.