ChemInform Abstract: Total Synthesis of Ionophores. Part 6. Asymmetric Induction in the Permanganate‐Promoted Oxidative Cyclization of 1,5‐Dienes.

Abstract

065ChemInform Abstract The oxidative cyclization of the enantiomerically enriched dienoate (I) functionalized with a chiral auxiliary gives products (II) + (III) with relatively low stereodifferentiation. Subsequent removal of the auxiliary provides the esters (V) or (VI). In contrast, high stereoselectivities are found when the bornane-10,2-sultam system is used as the chiral auxiliary. Thus, a 9:1 mixture of (IIa) and (IIb) is initially obtained from the compound (V), and the diol (IVa) can be subsequently isolated as the major product. In addition, the compound (VI) can be transformed to the ester (VII) using this methodology.