First prepare a polyfunctional isoquinuclidine by Diels-Alder condensation of a dihydropyridine with a dienophile and to subsequently replace one of the functionalities in the resulting adduct by a cyclic carbonyl group. Attempts to condense l-benzyl-3- cyano-l,6-dihydropyridine with a-acetoxyacrylonitrile, ethoxyacetylene, and nitroethylene did not yield isolable amounts of the anticipated isoquinuclidines, and subsequent efforts were directed toward the acquisition of an α,β-unsaturated primary amide which could be transformed to an isoquinuclidone by Hofmann degradation. Thus, reduction of N-benzyl-3- cyanopyridinium bromide with sodium borohydride in aqueous solution containing sodium carbonate gave an oily mixture of the yellow 1,2-dihydropyridine and the colorless 1,6-dihydropyridine separable only by thin layer chromatography. Condensation of the crude mixture of reduced pyridines with methyl vinyl ketone yielded the crystalline isoquinuclidine in 16% yield. Then from analogy with two similar Diels-Alder adducts 10 and 12 of established structure. Condensation of the dihydropyridine with methyl acrylate yielded the adduct 10 while analogous combination of 1 -benzyl-3 -carbomethoxy- 1,6-dihydropyridine (11) with acrylonitrile gave the isomeric compound 12. On catalytic hydrogenation both adducts furnished the same isoquinuclidine 13 characterized in the form of its crystalline hydrochloride. Since either substituent in the final product 13 can be derived from a 3-substituted pyridine, the functionality introduced by the dienophile and the basic nitrogen atom must be located on vicinal carbon atoms. Refrence DOI: 10.1021/ja00965a039