The condensation of 4-acetoxy-3,5-di-tert-butylphenol (I) with 2-chloro-N-(hydroxymethyl)acetamide (II) by means of H2SO4 in Ac-OH gives 4-acetoxy-3,5-di-tert-butyl-2-(2-chloroacetamidomethyl)phenol (III), which is hydrolyzed with HCl in ethanol to yield 4-acetoxy-2-/aminomethyl)-3,5-di-tert-butylphenol (IV). The oxidation of (IV) by means of hexamethylenetetramine (HMTA) affords the aldehyde (V), which is submitted to a Grignard condensation with 6-undecylmagnesium bromide (VI) in THF, followed by dehydration with conc. HCl to provide 4-acetoxy-3,5-di-tert-butyl-2-(2-pentyl-1-heptenyl)phenol (VII). The cyclization of (VII) by means of BF3/Et2O in dichloromethane gives the dihydrobenzofuran (VIII), which is finally deacetylated by reduction with LiAlH4 in THF to provide the target phenol.