Facile Utilisation of Aldehyde Bisulfite Adducts: Synthesis of (E)-1,2- Diphenylethenes

Background: A one-pot coupling reaction of aldehyde bisulfite adducts was developed for McMurry reaction using Zn-TiCl4 in 1,4-dioxane solvent medium. The treatment of sodium hydroxy( phenyl)methane sulfonate (2a) with TiCl4 in 1,4-dioxane favoured the deprotection of the bisulfite adduct 2a, and the in situ regeneration of benzaldehyde (1a) underwent reductive coupling to afford stilbene 3a in a relatively good yield, thus leading to an improved synthesis of a series of (E)-1,2- diphenylethenes 3. The present approach provides a new solution to the inherent instability of aldehydes and also provides a direct access to C–C bond formation for the synthesis of 1,2-diphenylethenes from aryl aldehyde bisulfite adducts. Keywords: Aromatic aldehyde, bisulfite adduct, 1, 4-dioxane, stilbene, TiCl4, Zn dust.