Anion-π Catalyst

Anion-π Enzymes

In this report, we introduce artificial enzymes that operate with anion-π interactions, an interaction that is essentially new to nature. The possibility to stabilize anionic intermediates and transition states on an π-acidic surface has been recently demonstrated, using the addition of malonate half thioesters to enolate acceptors as a biologically relevant example. The best chiral anion-π cat...

Anion–π interactions influence pK a values

Five 8-(4-R-phenyl)-1-naphthol derivatives were prepared by PdCl(2)-catalysed electrophilic aromatic substitution. The pK(a)' values for these 1,8-disubstituted arene naphthols have been measured in acetonitrile/water (R = NO(2), 8.42; R = Cl, 8.52; R = H, 8.56; R = Me 8.68; and R = OMe, 8.71) and indicate a correlation with the electronic nature of the arene substituent, as determined through ...

Towards design strategies for anion–π interactions in crystal engineering

Anion-π catalysis: bicyclic products with four contiguous stereogenic centers from otherwise elusive diastereospecific domino reactions on π-acidic surfaces.

Anion-π interactions have been introduced recently to catalysis. The idea of stabilizing anionic intermediates and transition states on π-acidic surfaces is a new fundamental concept. By now, examples exist for asymmetric enolate, enamine, iminium and transamination chemistry, and the first anion-π enzyme has been created. Delocalized over large aromatic planes, anion-π interactions appear part...

0 Observation of the φ → π + π − π + π − Decay

Using 11.6 pb of data collected in the energy range 0.984–1.06 GeV by CMD-2 at VEPP-2M, the cross section of the reaction e+e− → π+π−π+π− has been studied. For the first time an interference pattern was observed in the energy dependence of the cross section near the φ meson. The branching ratio of the φ → π+π−π+π− decay double suppressed by the G-parity and OZI rule is measured Br(φ → ππππ) = (...