Anthracene-9-carbinol

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... 

Table 6.2 Sodium and guanidinium salt effects (relative reaction rates) of Diels-Alder reaction of anthracene-9-carbinol and N-ethylmaleimide...

Another successful example of such guest design is the Diels-Alder reaction markedly accelerated by the cyclodextrin inclusion. As shown in Table XXIV, /J-cyclodextrin accelerates the addition of a small dienophile to cyclopentadiene, but inhibits that of N-ethylmaleimide to anthracene-9-carbinol (117). Thus, the guest design is a really helpful concept for the remarkable catalysis. However, there seems to be some limitation in the choice of reactions, if cyclodextrins have no special functional group for the... 

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-... 

We were interested in the possibility that Diels-Alder additions could be promoted if the two components bound into the same cavity in a cyclodextrin. We examined three examples 1,3-cyclopentadiene plus butenone, 1,3-cyclopentadiene plus acrylonitrile, and anthracene-9-carbinol plus N-ethylmaleimide (Fig. 1.19). We saw several interesting effects. First of aU, relative to the second-order rate constant in water, the addition of 10 mM -cyclodextrin... 

This reaction was initially studied by Anschutz between 1879 and 1886. It is the synthesis of anthracene from vinyl bromide and benzene in the presence of aluminum chloride. In addition, methyl phenyl carbinol or 1,1-diphenyl ethane can also be converted into anthracene derivative in the presence of aluminum chloride. 

The acid-catalyzed cyclization of an acyl substituted diarylalkane 1 into a cyclic carbinol 2, followed by a 1,4-dehydration to produce anthracene derivative 3, is known as the Bradsher Reaction. ... 

Bradsher proposed that the mechanism initially involved reversible addition of the proton to the carbonyl group of 1 to form 7, followed by intramolecular Friedel-Crafls-type electrophilic attack on the aryl ring by the positively charged species in 8.2,5,13-15 Restoration of aromaticity through proton loss from 9 followed by acid-catalyzed 1,4-dehydration of carbinol 2 furnished the anthracene derivative 3. 

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