Methyl methacrylate reaction with cyclopentadiene

The Diels-Alder reaction of methyl methacrylate with cyclopentadiene was studied [72] with solutions from three different regions of the pseudophase diagram for toluene, water and 2-propanol, in the absence and in the presence of surfactant [sodium dodecyl sulfate (SDS) and hexadecyltrimethylammonium bromide (HTAB)]. The composition of the three solutions (Table 6.11) corresponds to a W/O-fiE (A), a solution of small aggregates (B) and a normal ternary solution (C). The diastereoselectivity was practically constant in the absence and in the presence of surfactant a slight increase of endo adduct was observed in the C medium in the presence of surfactant. This suggests that the reaction probably occurs in the interphase and that the transition state has a similar environment in all three media. 

Table 6.11 Diastereoselectivity of Diels-Alder reaction of methyl methacrylate with cyclopentadiene performed in ternary solutions...

Holt studied the Diels-Alder reaction in a mixture of water, 2-propanol, and toluene as microemulsions.33 The endo/exo ratio between the reaction of cyclopentadiene and methyl methacrylate was enhanced with increasing amount of water in the presence of a surfactant. 

The Alder rule is not perfect. It correctly predicts the major product from the Diels-Alder reaction of 1,3-cyclopentadiene with methyl acrylate, but is incorrect in the case of methyl methacrylate. On the basis of these facts, give the structure of the major product isolated in each case. 

Diols are efficient bidentate ligands for Lewis acid metals such as Ti(IV). Starting from Merrifield resin, alkyl spacer-tethered 1,2- and 1,3-diol functionality was easily introduced to the cross-linked polymer [63]. The resulting polymer (130) containing diol functionality was treated with TiCU in toluene for 18 hours to give the polymer-supported Ti(IV) Lewis acid (132) (Scheme 19.26). These polymeric Ti(IV) catalysts were used for Diels-Alder reaction of cyclopentadiene (134) and methyl methacrylate (135). Although the polymer-supported Ti(IV) (132) catalyzed the reaction, their activities were lower than that of the nonsupported diol-Ti(IV) catalyst (131). 

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