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Synthesis and structural aspects of some intermediates in furofuran lignan synthesis

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.