Optically active cyclohexane moiety precursor for tetrodotoxin molecule was synthesized by Diels-Alder cycloaddition between a bromo derivative of levoglucosenone and Danishefsky type diene. The unstable product, bromo-ketone, was converted into vinylphosphinate and then the carbonyl compounds, to which the critical carbon nucleophile was predominantly introduced with alkynyltrifluroborate. The Lewis
河豚毒素分子的旋光活性
环己烷部分前体是通过左旋
葡糖醛酮的
溴衍
生物与Danishefsky型二烯之间的Diels-Alder环加成反应合成的。将不稳定的产物
溴酮转化为
乙烯基次膦酸酯,然后转化为羰基化合物,主要与三
氟硼酸炔基引入关键的碳亲核试剂。
路易斯酸在将选择性转向羰基碳或
磷原子方面起着重要作用。