Succinic acid dimethylene

Butadiene-2,3-dicarboxylic acid Succinic acid, dimethylene- (8), Butanedioic acid, bis(methylene)- (9) (488-20-0)... 

Dicarbonylation in aprotic solvents yields acid anhydrides. Fulgide (dimethylene-succinic anhydride derivative) 78 was obtained in 49% yield by the Pd(0)-catalysed dicarbonylation of 2,5-dimethyl-3-hexyne-2,5-diol (76) via 77 in benzene [6], The fulgide-forming reaction proceeds more smoothyl using Pd(OAc)2 as the catalyst in the presence of iodine (Pd l2 = 1 1) instead of hydrochloric acid [18]. 

---