An efficient, optimized, and scalable process for the synthesis of C-ring ester-functionalized prodigiosenes has been developed by (i) exploiting a silylative Mukaiyama aldol strategy for the condensation of alkyl 5-formyl-2,4-dimethylpyrrole-3-carboxylate and 4-methoxy-3-pyrrolin-2-one to form the corresponding ester-functionalized dipyrrinone analogues, and (ii) developing a facile synthesis of stable bromodipyrrin analogues for the use in formal Suzuki coupling reactions. The process was applied to the synthesis of three C-ring ester-functionalized prodigiosenes in multigram scales (up to 6.5 g prodigiosene free-base) with useful yields (35-56% overall yields over three steps starting from the 2-formyl pyrroles).
开发了一种高效、优化且可扩展的合成C环酯功能化灵菌红素的方法,该方法包括:(i)利用
硅烷化Mukaiyama醛醇策略,将烷基5-甲酰基-
2,4-二甲基吡咯-3-羧酸酯与
4-甲氧基-3-吡咯啉-2-酮缩合,形成相应的酯功能化双
吡咯酮类似物;(ii)发展了一种简便的稳定
溴化双
吡咯类似物的合成方法,用于正式的铃木偶联反应。该方法成功应用于三种C环酯功能化灵菌红素的合成,规模达到多克级(最多6.5克灵菌红素游离碱),产率良好(从2-甲酰基
吡咯开始,经过三步反应的总产率为35-56%)。