Author:

Keywords:

dearomatization; heterogeneous catalysis; silver nanoparticles; spirocyclization; spiroindolenines, Science & Technology, Physical Sciences, Chemistry, Physical, Chemistry, dearomatization, heterogeneous catalysis, silver nanoparticles, spiroindolenines, spirocyclization, SUPPORTED GOLD NANOPARTICLES, ENANTIOSELECTIVE CONSTRUCTION, ALLYLIC ALKYLATION, DERIVATIVES, REARRANGEMENT, CYCLIZATION, ACCESS, SPIROINDOLENINES, HYDROARYLATION, SELECTIVITY, 0302 Inorganic Chemistry, 0305 Organic Chemistry, 0904 Chemical Engineering, 3106 Industrial biotechnology, 3405 Organic chemistry, 3406 Physical chemistry

Abstract:

We present a supported silver-nanoparticle-catalyzed dearomatization of 3-substituted indoles toward 3-spiroindolenines. Two scaffolds were investigated for this transformation. The yields range from moderate to high. In the case of chiral reactants (Ugi four-component reaction adducts), the process is diastereoselective with a diastereomeric excess between 75% and 92%. The catalyst was characterized by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Metal leaching was investigated using hot-filtration and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) experiments. An apparent turnover frequency (TOF) was determined.