The Study On Coupling-cyclization Reactions Promoteded By Samarium/Copper

The thesis consists of two chapters. In the first chapter, theapplications of samarium reagents in synthetic organic methodology arebriefly described, which include metallic samarium, samarium diiodide,samarium triiodide, samarium/additive reagents and organosamariumreagent, and their respective usage in organic synthesis is discussed. It alsodescribes the reactions prometed by other lanthanide reagents, as well ascopper reagents. The second chapter described the reductive-couplingcyclization of aromatic aldehydes and acrylate promoted by samarium-copper.(1) The coupling-cyclization of aromatic aldehydes and methylacrylate promoted by Sm/CuI.(2) Structural identification of target molecule.(3) The reductive-coupling cyclization of aromatic aldehydesand other acrylate derivatives promoted by Sm/CuI.(4) Thereductive-coupling cyclization of aromatic aldehydes and methyl acrylatepromoted by Sm/CuCl/KI.(5) The reductive-coupling cyclization ofaromatic aldehydes and methyl acrylate promoted by other copper saltsand additives.(6) A plausible mechanism was proposed. The experimentalsection in which all of preparations and the operation procedures weredescribed in detail. All the title compounds obtained during theexplorations introduced in this article were characterized by1H-NMR,13C-NMR, IR and X-Ray single crystallography.Aromatic aldehydes and acrylate react reductive-coupling cyclizationprocess readily when promoted by samarium metal in THF with copper(I)iodide or copper(I) chloride/potassium iodide as a co-additive, to afford3-(hydroxylarylmethyl)-5-aryldihydrofuran-2-one in moderate to excellentyields. In some cases, benzoin was also obtained as the unexpectedproducts. The reactivities of a multitude of copper salts were explored. All the reactions in this paper were performed under nitrogen atmosphere.THF was distilled in sodium/benzophenone before use. The distribution ofyield and affecting factors were also discussed in detail and summarized.This is the first attempt to search for a practical and efficient reagentfor expanding the applications of samarium reagents in our group.Excluding the pinacol-coupling-type reactions of aldehydes, thistransformation constitutes the first example in which a new C C bond isformed by samarium in the presence of copper reagent. In addition, thereductive-coupling cyclization is also a highly efficient fashion for thesynthesis of3-(hydroxylarylmethyl)-5-aryldihydrofuran-2-one fromaromatic aldehydes and acrylate with more facile manipulation.