Functionalized dienes are versatile reagents in organic synthesis, [1] in particular as partner in Diels-Alder reaction. [2] Also their synthetic uses as organometallic (mainly organoiron) complexes are well documented. [3] In this context, diastereomerically pure 4-acetoxypenta-2,4-dienal derivatives 1 (R′ = H, CH 2 OAc) (Figure [1] ) may constitute interesting synthetic building blocks, [4] provided that their synthesis and isolation could be conveniently achieved from inexpensive ...