Titanocene(III) chloride mediated formal synthesis of magnofargesin and 7′-epimagnofargesin

Formal synthesis of two bioactive lignans, magnofargesin and 7′-epimagnofargesin has been accomplished in both racemic and optically active forms through titanocene(III) chloride (Cp2TiCl) mediated radical induced cyclization reaction. Ti(III) species was generated in situ from the commercially available titanocene dichloride (Cp2TiCl2) and activated zinc dust in dry THF.