Synthesis and Absolute Configuration of Wybutine, the Fluorescent Minor Base from Phenylalanine Transfer Ribonucleic Acids.
作者:Taisuke ITAYA、Akemi MIZUTANI、Takehiko IIDA
DOI:10.1248/cpb.39.1407
日期:——
The phosphonium chloride 6 having an optically active amino acid moiety was synthesized from (S)-serine benzylester tosylate (2b) through a six-step route. The utility of 6 as a reagent for the Witting reaction was exemplified in the olefination with benzaldehyde, affording the (E)-β, γ-unsaturated amino acid derivative 11 as a sole geometrical ispmer. This new method of amino acid homologation was successuflly employed for the first chiral synthesis of wybutine (1c), the minor base isolated from yeast phenylalanine transfer ribonucleic acids : the Wittig reaction between 6 and the tricyclic aldehyde 16 followed successively by methylation and catalytic reduction afforded 1c. Comparison of wybutine with synthetic 1c has unequivocally established that wybutine has an S configuration.
含有光学活性氨基酸部分的氯化膦 6 是通过一条六步合成路线从 (S)-丝氨酸苄酯对甲苯磺酸酯 (2b) 合成的。6 作为 Witting反应试剂的实用性在苯甲醛的烯化反应中得到了体现, 得到了唯一的 (E)-β, γ-不饱和氨基酸衍生物 11。这种新的氨基酸同系化方法成功地应用于黄曲霉素 (1c)的首次手性合成, 黄曲霉素是从酵母苯丙氨酸转移核糖核酸中分离得到的次要碱基。6 与三环醛 16 的 Wittig 反应之后接着进行甲基化和催化还原,从而得到了 1c。黄曲霉素与合成物 1c 的比较明确地证明了黄曲霉素具有 S 构型。