Asymmetric Synthesis of a Hydroxylated Nine-membered Lactone from Tartaric Acid using the Claisen Rearrangement

Abstract

The synthesis of a hydroxylated vinyl-appended lactone, in five synthetic steps from tartaric acid, is reported. The C2-symmetrical bis-vinyl diol 12 was converted into the ketene acetal 14 via methylenation of the cyclic carbonate 13 or thermal elimination of benzeneselenenic acid from the selenoxide 17. In both cases, the in situ generated ketene acetal 14 underwent spontaneous Claisen rearrangement to give the nine-membered lactone (+)-15. Lactones of this type are potentially advanced precursors to simplified eleutherobin analogues or other medium-ring lactone natural products.