Cyclopentadiene methylacrylate

In contrast, modest enantioselection has been observed in the asymmetric Diels-Alder reaction between cyclopentadiene (18) with methylacrylate and methylpropiolate catalyzed by chiral organoaluminum reagents 58 [59] (Equation 3.15) prepared from trimethylaluminum and (R)-(+)-3,3 -bis(triphenylsi-lyl)-l,l -bi-2-naphthol [60]. The reaction was highly cnJo-diastereoselective. 

During the reaction of cyclopentadiene with methylacrylate, higher temperatures in combination with longer reaction times lead to a shift in the endoiexo ratio from 1 1 to 3 1. This is contradictory to frontier orbital calculations predicting a loss of mdo exo selectivity in supercritical water because of the loss of the hydrophobic effect [48]. 

The impact of acidic and basic ionic liquid melts (l-ethyl-3-methylimidazolium chloride) on the rates of the Diels-Alder reaction between cyclopentadiene and methylacrylate has been investigated with the PDDG/PM3 method for the QM part and the OPLS force field for the solvent molecules. The ability of the ionic liquid to act as hydrogen bond donor (cation effect), moderated by its hydrogen bond... 

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