Scope and Limitations of Supramolecular Autoregulation

Abstract

Recently, our group has reported on the ureidopyrimidinone (UPy) induced buffering of 2,7-diamido-1,8-naphthyridine (NaPy) and used this phenomenon to regulate the catalysis of the Michael addition of 2,4-pentanedione to trans-β-nitrostyrene. We now show that the observed catalytic activity of NaPy is the result of a strong synergy between NaPy and trace amounts of K₂CO₃, resulting in a more than 100-fold increase in reaction rate compared to the two compounds separately. By keeping the concentration of K₂CO₃, as well as NaPy, constant, an improved regulation of the catalytic activity is achieved. We show that the catalytic activity can be precisely regulated in a noncovalent manner via the addition of the UPy motif. Finally, different salts and Michael substrates are screened to assess the selectivity of this catalytic couple and to provide a platform for future research in molecular buffering, regulation, and chemical networks.

We report on the use of 2,7-diamido-1,8-naphthyridine as phase-transfer catalyst for the Michael addition, whose activity can be regulated in a noncovalent manner via the complementary ureidopyrimidinone motif. The influence of this finding on previously reported results is discussed.