Azabicyclo octane Diels-Alder reactions

To generate molecular libraries, a series of 5-oxo-2-azabicyclo[2.2.2]octane and triaza analogs were prepared via a stereospecific Diels-Alder reaction by reacting Wang-resin-bound diene 35 with a variety of dienophiles [28]. After removing the solid support with a strong acid, adducts 36 were isolated examples of reactions that have furnished the best yields are reported in Scheme 4.6. 

In a different approach to performing hetero Diels-Alder reactions in water, Pier-matti reported three-component aza Diels-Alder reaction of 2-cyclohexen-l-one, aniline and aldehyde in water in the presence of a-zirconium hydrogenphosphate (a-ZrP) and SDS for the synthesis of diaiyl-2-azabicyclo[2.2.2]octan-5-ones 53 [39], The reactions performed in water at room temperature had higher exo selec-tivities than in organic solvents (Scheme 1.26). 

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