The total syntheses of two acetogenins, squamocin A and squamocin D, have been achieved. The adjacent bis-THF subunit was constructed by a multiple Williamson reaction. The left and the right side chain were added by addition of organomagnesium compounds to aldehyde functions. The conversion of a carboxylic acid into the butenolide moiety concluded both syntheses. (C) 1999 Elsevier Science Ltd. All rights reserved.