Towards Reaction Control: An Expeditious Access to Racemic 5-Substituted Tetramates and 5-Substituted Tetramic Acids from Malimides

摘要: A versatile and divergent two-step transformation of malimides to racemic tetramates tetramic acids is described. The method consists Grignard reagent addition with give hemiaminals concentrated HCl-promoted chemoselective transformations the latter. When running reaction in CH2Cl2 presence 2.5 molar equiv. conc. HCl, 5-alkyltetramates were formed, while neat 5-alkyltetramic obtained. Using this method, a variety title compounds prepared good excellent yields (82%–99%, 76%/85%). work also constitutes formal total synthesis reutericyclin. On basis experimental evidences deuterium labeling experiment, plausible mechanism was proposed. This thus demonstrated two new types step economical chemodivergent starting from malic acid.