Regioselective NaBH₄ and DIBAL-H reductions of 3,4-dimethoxyhomopiperonyl­phthalimide: Concise and efficient synthesis of nuevamine and isonuevamine

868-871Facile synthesis of nuevamine and isonuevamine has been reported via the regioselective reduction of hindered and un­hindered carbonyl groups of 3,4-dimethoxyhomopiperonyl­ph­thalimide, respectively using sodium borohydride and di­isobutyl­­aluminum hydride, followed by an acid catalyzed intra­molecular dehydrative cyclization pathways. The chemistry involved in obtaining the regioselectivity has been discussed in brief

Base-Mediated Hydroamination of Propargylamine: A Regioselective Intramolecular 5-<i>exo-dig</i> Cycloisomerization en Route to Imidazole-2-thione

An intramolecular transition-metal-free base-mediated hydroamination of propargylamine with isothiocyanates has been achieved. This atom-economical, regioselective intramolecular 5-<i>exo-dig</i> cycloisomerization was utilized for the one-pot synthesis of diversely substituted imidazole-2-thione and spiro-cyclic imidazolidine-2-thione. The reaction goes to completion at room temperature via propargylthiourea and 65–97% isolated yields were obtained