106(P36) トマト宿主特異的毒素AAL-toxin TAの立体構造および合成研究(ポスター発表の部)

概要

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AAL-toxins TA_1 1 and TA_2 2 are host-specific toxins (HST) produced by Altemaria altemata f. sp. lycopersici, a causal fungus of tomato stem canker. For understanding the mechanism of the host-specificity of AAL-toxins in molecular level, the elucidation of the stereostructure and synthetic studies are essential. In order to determine the absolute configuration, AAL-toxins TA_1 1 and TA_2 2 were degraded to 2-methylbutanol, 3-methylnonan-1,9-diol and N-protected 4-amino-butan-1,3-diol, which were further converted to (R)-MTPA esters, These esters were correlated with synthetic samples by comparison of their 500MHz ^1H-NMR spectra. The remaining stereocenters were determined by the comparison of ^1H-NMR spectra of 6a and 6c derived from 1 and 2 with those of synthetic model compounds. These data concluded that AAL-toxins possess 2S, 4S, 5S, 11S, 13S, 14R and 15R configurations. To the syntheses of two vicinal anti-diol moieties in key intermediates of AAL-toxins, asymmetric dihydroxylation has been applied. The strategy allowed efficient construction of left- and right segments of AAL-toxin main chain. Enzymatic resolution of benzylsuccinate ester provided both enantiomers (R)-39 and (S)-40 which were converted to the corresponding tricarballylic acids. Effective couplings of each segment were also investigated.
天然有機化合物討論会の論文
1996-09-02