Synthesis of Some Novel Functionalized Monoazatricyclic Ring Systems via Intramolecular Cycloaddition of N-(Bicycloalkenyl)nitrones

Article abstract of DOI:10.1021/jo00211a022

The intramolecular cycloaddition of C-phenyl-N-(endo-bicyclo<3.2.1>oct-6-en-3-ylmethyl)nitrone (3) geneerated in situ from the corresponding hydroxylamine and benzaldehyde gave the adduct 4 in a high yield.Reductive cleavage of 4 afforded 2-endo-hydroxy-4-endo-phenyl-5-azatricyclo<5.3.1.0^3,9>undecane (6).The intramolecular cycloadditions of unsymmetrical N-(endo-bicyclo<2.2.1>hept-5-en-2-ylmethyl)nitrones (11a,b) and N-(endo-bicyclo<2.2.2>oct-5-en-2-ylmethyl)nitrones (23a,b) occurred regiospecifically to afford the adducts 12a, b and 24a,b, respectively.Reductive cleavage of these adducts provided a convenient route to functionalized 5-azatricyclo<5.2.1.0^3,8>decanes (15a,b, 16, 17) and 5-azatricyclo<5.3.1.0^3,8>undecanes (27a,b, 28, 29), respectively.The regiochemical and stereochemical assignments of 12a and 24a were proven by X-ray analysis of the methiodides 14a and 26a.