engleski

Engineering Exceptionally Strong Oxygen Superbases with 1, 8-Diazanaphthalene di-N-oxides

For more than four decades, the design and synthesis of neutral organic superbases have attracted much attention1 because their unique characteristics allow deprotonation of a wide range of weak acids. Although usually weaker than their inorganic counterparts, uncharged organobases have become widely used standard reagents in organic synthesis. DFT calculations revealed that naphthalenes bearing two 1, 8-bis-substituted N–oxides provide extraordinary oxygen superbases, whose gas-phase and acetonitrile basicities surpass those of classical nitrogen proton sponges involving naphthalenes equally di-substituted with dimethylamino, guanidino, and phosphazeno groups. Such pronounced basicity is almost entirely a consequence of a large strain-induced destabilization in neutral bases, while only a small contribution is offered by the intramolecular [O–H·····O]– hydrogen bonding in conjugate acids.2 References: 1. Ishikawa, T. Superbases for Organic Synthesis: Guanidines, Amidines, Phosphazenes and Related Organocatalysts ; Wiley: New York, 2009. 2. Despotović, I., Vianello, R. Chem. Commun. 2014, 50, 10941-10944.

superbases

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