Anthracene reaction with acrylonitrile

In order to develop catalytic effects of cyclodextrins for bimolecular reactions, it needs to include two guest molecules simultaneously in a cyclodextrin (CD) cavity. Several examples of cyclodextrin-catalyzed bimolecular reactions have been reported. Rideout and Breslow have found that Diels-Alder reactions of cyclo-pentadiene with butenone, cyclopentadiene with acrylonitrile, and anthracene-9-carbinol with N-ethylmaleimide in water are markedly accelerated by 3-cyclodextrin (3-CD) (1). Komiyama and Hirai have reported site-selective Reimer-Tiemann reactions of phenols in cyclodextrin solutions (2). In most of these reactions, however, each substrate molecule is relatively small so that a 3-CD cavity may include simultaneously an additional reactant molecules. We found previously that the fluorescence quenching of pyrene and naphthalene by trimethylamine (TMA) or dimethylamine (DMA) in water is catalyzed by g-CD (3) Since the pyrene molecule is too large to be incorporated completely in the 3-CD cavity, it has been assumed that pyrene binds to a rim of the CD cavity to form a pyrene-capped CD complex and a remain-... 

Rideout and Breslow first reported [2a] the kinetic data for the accelerating effect of water, for the Diels Alder reactions of cyclopentadiene with methyl vinyl ketone and acrylonitrile and the cycloaddition of anthracene-9-carbinol with N-ethylmaleimide, giving impetus to research in this area (Table 6.1). The reaction in water is 28 to 740 times faster than in the apolar hydrocarbon isooctane. By adding lithium chloride (salting-out agent) the reaction rate increases 2.5 times further, while the presence of guanidinium chloride decreases it. The authors suggested that this exceptional effect of water is the result of a combination of two factors the polarity of the medium and the... 

Similarly, with the acrylonitrile reaction the 10 mM -cyclodextrin increased the water rate by a factor of 9, while 5 mM a -cyclodextrin slowed it by a factor of 1.2. With the larger anthracene case, even /3-cyclodextrin slowed the water reaction, by a factor of 1.6, since the anthracene filled the cavity and did not permit simultaneous binding of the dienophile. However, the more striking rate effects were seen with the water solvent alone. 

---