Formal Total Synthesis of Fostriecin by 1,4-Asymmetric Induction with an Alkyne-Cobalt Complex
作者:Yujiro Hayashi、Hirofumi Yamaguchi、Maya Toyoshima、Kotaro Okado、Takumi Toyo、Mitsuru Shoji
DOI:10.1002/chem.201000795
日期:2010.9.3
4‐relationship is considered difficult, we have developed a notable 1,4‐asymmetric induction that utilizes an alkyne–cobalt complex for the control of C5 stereochemistry by the C8 stereogenic center. The stereochemistry at C11 was established by 1,3‐asymmetric induction with a higher‐order alkynyl‐zinc reagent. Thus, only one asymmetric reaction requiring an external chiral auxiliary was employed in this
已经完成了受保护的去磷酸钙丝素的合成,从而正式合成了泊丝汀。合成方面的挑战是建立四个立体基因中心和构象不稳定的顺式-顺式-反式-三烯部分。先前的总合成已经使用了至少两个不对称反应,这需要使用外部手性助剂。尽管认为在1,4关系中进行远程立体诱导很困难,但我们开发了一种显着的1,4-不对称诱导,利用炔-钴复合物通过C8立体异构中心控制C5立体化学。C11的立体化学是通过用较高级的炔基锌试剂进行的1,3-不对称诱导建立的。因此,在该途径中仅使用了一个需要外部手性助剂的不对称反应。不稳定的顺式-顺式-反式三烯单元是在合成的后期通过二烯炔和醛单元的非对映选择性偶联而构建的,然后还原。