A Second-Generation Total Synthesis of (+)-Discodermolide: The Development of a Practical Route Using Solely Substrate-Based Stereocontrol
作者:Ian Paterson、Oscar Delgado、Gordon J. Florence、Isabelle Lyothier、Matthew O'Brien、Jeremy P. Scott、Natascha Sereinig
DOI:10.1021/jo048534w
日期:2005.1.1
subunits, aldehyde 9 (C1−C5), ester 40 (C9−C16), and aldehyde 13 (C17−C24), was established via a boron-mediated aldol reaction of ethyl ketone 15 and formaldehyde, followed by hydroxyl-directed reduction to give 1,3-diol 14. Alternatively, a surrogate aldehyde 22 was employed for formaldehyde in this aldol reaction, leading to the β-hydroxy aldehyde 20 as a common building block, corresponding to the discodermolide
复杂的聚酮化合物(+)-discodermolide(一种有希望的海绵状抗癌剂)的新颖的全合成方法,以24个线性步骤(共35个步骤)完成了7.8%的总收率。第二代方法设计为仅依靠底物控制来引入所需的立体化学,而无需使用所有手性试剂或助剂。常见的1,2-抗-2,3- -syn立体三元组存在于以下三个亚基中:醛9(C 1 -C 5),酯40(C 9 -C 16)和醛13(C 17 -C 24)),是通过乙酮15和甲醛的硼介导的醛醇缩合反应建立的,然后通过羟基直接还原得到1,3-二醇14。备选地,在该醛醇缩合反应中,将替代醛22用于甲醛,从而导致β-羟基醛20作为共同的结构单元,对应于二茂铁立体异构体。关键片段的结合是通过在Felkin-Anh控制下酯40和醛13的锂介导的抗羟醛缩合反应实现的,以提供(16 S,17 S)加合物51和烯酮10之间的硼介导的羟醛缩合反应。和醛9,利用前所未有的远程1