Synthesis and structural aspects of some intermediates in furofuran lignan synt...

• Author(s): Esteves, Ana Paula ; Lemos, Maria A. ; Medeiros, Maria José ; Rodrigues, Lígia M.
• Date: 2004
• Persistent ID: http://hdl.handle.net/1822/1960
• Origin: RepositóriUM - Universidade do Minho
• Subject(s): Radical cyclisation; Hypophosphite salt; Furofuran lignans
• Document Type: Article
• Language: English

Description

The synthesis of some intermediates of furofuran lignans was accomplished by a chemical cyclisation reaction using N-ethylpiperidine hypophosphite and azobisisobutyronitrile. This reaction afforded the 5-exo-dig cyclic compound as the major product along with another isomeric cyclic compound which possess an endocyclic double bond. A brief discussion is presented to explain the formation of these isomeric cyclic compounds by a base-catalysed tautomerism mechanism. Some structural aspects are discussed based on nuclear magnetic resonance data.