Stereocontrolled Synthesis of the C1‐C10 Fragments of Monensin B and Laidlomycin

An efficient synthetic route to the C1‐C10 fragments of laidlomycin and monensin B has been developed toward their total synthesis. The asymmetric carbons have been elaborated by a syn ‐aldol reaction using the oxazolidinone chiral auxiliary for C6 and C7, an anti ‐aldol reaction for C3 and C4, the Tishchenko–Evans reaction for C5, and a chiral building block for C2.