Preparation and Application of Solid, Salt-Stabilized Zinc Amide Enolates with Enhanced Air and Moisture Stability

The treatment of various N-morpholino amides with TMPZnCl center dot LiCl (TMP= 2,2,6,6-tetramethylpiperidyl) and Mg(OPiv)(2) in THF at 25 degrees C provides solid zinc enolates with enhanced air and moisture stability (t(1/2) in air: 1-3 h) after solvent evaporation. These enolates undergo Pd-and Cucatalyzed cross-couplings with (hetero) aryl bromides as well as allylic and benzylic halides. The arylated N-morpholino amides were converted into various ketones by LaCl3 center dot 2 LiCl mediated acylation with Grignard reagents. The new, solid enolates were used to prepare a potent anti-breast-cancer drug candidate in six steps and 23% overall yield.