The efficiency of this synthetic procedure strongly depends on the reactivity of the Michael acceptors. Thus, the reaction of cyclic enones such as 2a, 2b, 2c, and 2g with nitrogen heterocycles such as 1a, pyrazole (1c), benzotriazole (1e), and purine (1g) gave the corresponding adducts 3b, 3c, 3h, 3l, 3o, 3q, and 3r in excellent yields (entries 1, 2, 6, 9, 12, 14, Table [2] ). In the last example, a mixture of the N9- and N7-alkylated regioisomers (3q and 3r) was obtained in ...
