Oh the irony, kg's of succinic acid, and hundreds of grams of the anhydride, but there is no literature to get the aldehyde from either of these. There are a variety of very elementary chemical procedures that yeild aldehydes. Make the acid chlordie form succinic acid, the treat with LiAlH(O-tBu)3 is one. There is a whole host of simple transformations that could be used on this highly functional carboxylic acid, I wonder why none have been cited?