Tetraethylammonium 2-(N-hydroxycarbamoyl)benzoate: a powerful bifunctional metal-free catalyst for efficient and rapid cyanosilylation of carbonyl compounds under mild conditions

In contrast to tetrabutylammonium hydroxide, its tetraethylammonium counterpart reacts with N-hydroxyphthalimide to afford tetraethylammonium 2-(N-hydroxycarbamoyl)benzoate (TEAHCB) rather than tetraethylammonium phthalimide-N-oxyl (TEAPINO). TEAHCB contains at the same time benzoate and hydroxycarbamoyl functionalities in a proper geometry to activate reaction components as Lewis basic and Lewis acidic centers, respectively. TEAHCB was found to be able to efficiently catalyze very rapid cyanosilylation of a wide variety of carbonyl compounds at 0.15 mol% catalyst loading under solvent-free conditions at room temperature as a simple and readily available bifunctional organocatalyst.