Cycloadditions of Cycloalkenones

2 CARBON DIELS-ALDER REACTION 3.2.1 Cycloadditions of Cycloalkenones 

Diels-Alder reactions of conjugated cycloalkenones provide a very important method for rapidly constructing complex polycyclic molecules. Since cycloalkenones are very poorly reactive dienophiles, acceleration by special physical and catalytic methods is required in order to avoid high reaction temperatures and long reaction times which often lead to low product yields [8], 

A broad study of aluminum chloride-induced cycloadditions of cyclopente-nones, cyclohexenones and cycloheptenones with 1,3-butadiene (1), isoprene 

A strong dependence of the diastereofacial selectivity [18] on the substituents has been observed in the catalyzed cycloadditions of acyclic dienes with 

The presence of two substituents at C-4 also strongly influences the regios-electivity as shown in the cycloaddition of dienone 13 with isoprene (2) (Equation 3.1). In violation of the para-rule for Diels-Alder reaction, only metfl-adduct was obtained [19,20]. 

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