Toward Efficient Nucleophilic Azaborine Building Blocks for the Synthesis of B–N Naphthyl (Hetero)arylmethane Isosteres

To develop a method for the synthesis of a class of azaborines, potassium 2-(trifluoroboratomethyl)-2,1-borazaronaphthalenes have been synthesized to serve as nucleophilic building blocks. In palladium-catalyzed cross-coupling reactions with (hetero)aryl chlorides they serve to produce a variety of pseudobenzylic (hetero)aryl substituted azaborines. Potassium 2-(trifluoroboratomethyl)-2,1-borazaronaphthalenes are crystalline solids that are more stable than 2-(chloromethyl)-2,1-borazaronaphthalenes and have a broader substrate scope in cross-coupling reactions compared to their pseudobenzylic chloride counterparts.