Scheme 6. 1,4-Addition and Reduction Transformations of Compounds 1a and 1b.
Reactants and conditions: (a) H2, Pd/C (10 mol %), MeOH, H-Cube, rt, 30 min; (b) CeCl3·7H2O(1.0 equiv), then NaBH4 (1.0 equiv), DCM, MeOH, rt, 15 min; (c) NiCl2·6H2O (0.5 equiv), NaBH4 (5.0 equiv), DCM, MeOH, rt, 1.5 h; (d) pyrrolidine (1.5 equiv), EtOH, rt, 5 min.