Cyclopentadiene, derivatives conclusion

Chapter 5, may provide a rationale. Conclusions derived from a number of H-MVIR measurements indicate that cyclopentadiene has a high affinity for the interior of the micelles that were investigated, whereas the dienophile prefers the outer regions. In view of the structures of most dienes and dienophiles such a spatial separation can be expected for the majority of Diels-Alder reactions. This arrangement accounts for the unexpectedly small influence of micelles on the rates of Diels-Alder reactions as reported in the literature. 

Reactions of optically pure sulfinyl enones with acyclic dienes have never been reported, perhaps as a result of the discouraging results obtained from racemic substrates [56]. The reaction of a-phenylsulfinyl a,/i-unsaturated ketones with butadiene and 2,3-dimethyl butadiene, under Lewis acid catalysis, yielded the cyclohexadienes resulting from spontaneous elimination of sulfenic acid (precluding any conclusion about the stereoselectivity of the reaction). Analogous results were found by Nishio et al. [57] from reactions of /i-phenylsulfinyl a,/l-unsaturated ketones with acyclic dienes. The bicyclic adducts derived from cyclopentadiene are more stable [57]. In this case, the reactions gave only the exo-sulfinyl adduct,but these stereochemical results were neither confirmed nor discussed in the paper. 

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