Reaction Study Of Dicyanoethylenes In Samarium/TMSCl/DMF

The dissertation consists of two chapters. In the first chapter, the application of samarium reagents in organic synthesis is briefly described. The second chapter describes two parts of contents. Firstly, the intermolecular coupling and disilylation reactions of 1,1-diaryl-2,2-dicyanoethylenes promoted by Sm/DMF/TMSCl, then its intermolecular coupling cyclization reations with aldehydes or ketones were studied in succession. Secondly, the disilylation and decyanation reactions of l-alkyl-l-aryl-2,2-dicyanoethenes promoted by Sm/DMF/TMSCl, the simple reduction of l-alkyl-l-aryl-2,2-dicyanoethenes was studied finally.Charpter one introduces the usaual types of samarium reagents, which include metallic samarium, samarium(II) iodide, samarium(III) iodide, samarium/auxiliary reagents and allylsamarium bromide, and their respective usage in organic synthesis is discussed. It also describes the reactions prometed by other metals in DMF .Chapter two mainly described the reactions of dicyanoethylenes in Sm/DMF/TMSCl. It contains three parts: (1) The intermolecular reductive coupling cyclization and disilylation of l,l-dicyano-2,2-diarylethenes promoted by samarium/TMSCl in DMF was described. When l,l-dicyano-2,2-diarylethenes were treated in DMF with samarium/TMSCl, unexpectedly, intermolecular coupling and disilylation products were obtained, which offers a new approach to the synthesis of polysubstituted indenes. (2) The intermolecular reductive coupling cyclizalion and disilylation of l-alkyl-l-aryl-2, 2-dicyanoethenes promoted by Sm/TMSCl in DMF was described. Then, the simple reduction products of l-alkyl-l-aryl-2, 2-dicyanoethenes appeared when the traced H2O was in existence. When alcohols appeared in this system, only complex compounds were prepared. (3) Intramolecular reductive coupling cyclization of l,l-diaryl-2,2-dicyanoethylenes with aldehydes or ketones to synthesize polysubstituted 2,3-dihydrofurans promoted by Sm/DMF system was studied . Most of the reactions mentioned above are synthetically valuable and bear such advantages as mild reaction conditions, simple operation and good yields. All the compounds obtained via the reactions described in this dissertation were characterized by IR , 1H NMR, MS and/or 13C NMR, element alanalysis.