101(P26) フリルグリセロールをキラル合成素子とする多酸素官能性天然物の合成研究(ポスター発表の部)

概要

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We have demonstrated the synthetic utility of furylglycerols as chiral building blocks for highly oxygenated natural products syntheses. Enatioselective synthesis of monocrotalic acid, the necic acid of the macropyrrolizidine alkaloid monocrotalin, has been achieved by employing (2S, 3S)-furylglycerol 9 as the starting material. Ring enlargement of 9, followed by silylation of lactol 10 afforded silyl ether 11. Partial reduction of diene 13 and dihydroxylation of enone 14 proceeded stereoselectively to give diol 17 possessing the desirable chiral centers. Conversion of 17 into monocrotalic acid methylene acetal 7 was carried out using the glycol cleavage of triol 21 as a key step. Studies on the synthesis the bicyclic core of the zaragozic acids have been accomplished by the utilization of (2S, 3S)-furylglycerol 29. The key features are the diastereoselective dihydroxylation of enone 30 followed by reduction of ketone 32 to control the stereochemistries at the C4-C6 positions of the target molecule. Addition of lithium trimethylsilylacetylide to aldehyde 40 provided propargyl alcohol 41, which was further transformed into the bicyclic compounds 45 and 46. Compound 45 would be a potent intermediate for the synthesis of zaragozic acids.
天然有機化合物討論会の論文
1996-09-02