Synthetic studies on the marine natural product halichondrins
Synthetic studies on the marine natural product halichondrins
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海洋天然产物软海绵素的合成研究
DOI：
10.1351/pac200375010001
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发表时间：
2003
影响因子：
1.8
通讯作者：
Chaoyu Xie
中科院分区：
文献类型：
--
作者：
Hyeong;D. Demeke;Fu;Yoshito Kishi;Katsumasa Nakajima;Pawel Nowak;Zhao;Chaoyu Xie
摘要：结合软海绵素B右半部分及其类似物E7389的实际合成的发展，报道了两种主要构建块的有效和可扩展的合成。此外，还提出了一种新的通过区域特异性和立体选择性SN2’工艺合成C20-C26片段的方法。在化学计量和催化条件下，磺胺类配体对Ni/ cr介导的不对称反应有效，并且x射线结构显示该类配体为三齿体。在三个x射线结构的基础上，提出了这一过程的可能机制。稳定性和结晶性的Cr(III)/磺胺配合物可有效催化Cr介导的烯丙基、烯丙基和烷基卤化物与醛的偶联反应，并给出了一些应用于化学计量和催化不对称过程的例子。
Abstract In connection with the de elopment of a practical synthesis of the right half, and its analog E7389, of halichondrin B, an efficient and scalable synthesis of the two major building blocks is reported. In addition, a new synthesis of the C20–C26 segment via a regiospecific and stereoselecti e SN2' process is presented. A sulfonamide class of ligands is shown to be effective for asymmetric Ni/Cr-mediated reactions under both stoichiometric and catalytic conditions, and the X-ray structure reveals this class of ligands to be tridentate. On the basis of three X-ray structures, a possible mechanism is suggested for this process. Stable and crystalline Cr(III)/sulfonamide complexes are shown to be effective for catalytic Cr-mediated coupling reactions of allyl, alkenyl, and alkyl halides with aldehydes, and some examples for application of the stoichiometric and catalytic asymmetric processes are presented.