高立体選択的な天然物合成

キラルなグリセリン誘導体を基質とする天然物のエナンチオ選択的合成

抄録

Utility of a chiral glycerin derivative [(S) -1] as a versatile substrate for the enantioselective syntheses of natural products is described. The glycerin derivative [(S) -1] is converted into both enantiomers of the chiral γ-butyrolactone (3) which are in turn transformed to a -monosubstituted lactones (31) and α, α -disubstituted lactones (34) by stereoselective alkylation under kinetic conditions. Inversion of the α center of the monoalkylated lactone 31 is simply achieved by brief exposure of the enolate (32) derived from 31 to saturated aqueous sodium sulfate solution to give (33). α-Aryllactone derivatives (28) which cannot be obtained from the lactone substrate (3) are efficiently prepared from the epoxide (2) obtained from the glycerin derivative (1) and an appropriate phenylacetonitrile.
Using the lactone intermediates thus obtained, a dozen of optically active compounds ranging from monoterpenes and alkaloids to a β-lactam derivative illustrated in Fig. 1 are synthesized enantioselectively.