ABSTRACT
The enantioselective synthesis of polypropionates continues to be an attractive realm for the synthetic chemists mostly due to the challenges presented by the number of consecutive stereogenic centers contained within the aliphatic chain. Over the years, our laboratory has developed an epoxide-based three-step reiterative methodology for the construction of these targets, with the ultimate goal that the approach could be extended to the synthesis of polypropionate-containing natural products. The key steps include the diastereoselective epoxidation of allylic and homoallylic alcohols, and the regioselective cleavage of 2-methyl-3,4-epoxy alcohols. The choice of the organometallic reagent, and the cis/trans geometry of the chiral epoxide can be used to control both the relative and absolute configuration of the resulting propionate unit, allowing our approach to be applied in the synthesis of advanced fragments. Additionally, the combination of our first- and second-generation methodologies permits the incorporation of different variations at the methyl moiety.
ABSTRACT
The title compound, C11H18O4, consists of an anti,anti,anti-stereo-tetrad with a 1,2-carbonate and an alkene motif. The mol-ecule displays a common zigzag conformation. The five-membered ring has a twisted conformation on the C-C bond. In the crystal, a strong inter-molecular hydrogen bond between the hy-droxy group and the carboxyl-ate moiety from an adjacent mol-ecule forms chains propagating along the b-axis direction. The absolute structure of the mol-ecule in the crystal was determined by resonant scattering [Flack parameter = 0.05â (6)].
