A Gold-Catalyzed Entry into the Sesquisabinene and Sesquithujene Families of Terpenoids and Formal Total Syntheses of Cedrene and Cedrol
作者:Alois Fürstner、Andreas Schlecker
DOI:10.1002/chem.200801382
日期:2008.10.20
into the bicyclic cyclopropyl ketone derivatives 5 and 6 by way of a gold-catalyzed Ohloff-Rautenstrauch-type enyne cycloisomerization is described. The required substrates were prepared by an asymmetric addition of the branched allylzinc reagent 21 to the alkynyl aldehyde 17 mediated by the deprotonated bisoxazoline (BOX) ligand 22. Compounds 5 and 6 were then converted into a host of different members
描述了通过金催化的Ohloff-Rautenstrauch-型烯炔环异构化的方法简单地进入双环环丙基酮衍生物5和6。通过将非支化的烯丙基锌试剂21不对称地添加到由去质子化的双恶唑啉(BOX)配体22介导的炔基醛17中来制备所需的底物。然后将化合物5和6转化为倍半胱氨酸和倍半熟的不同成员的主体。萜类化合物,尤其是在铁催化的交叉偶联反应的帮助下。由于可以清楚地确定5和6的相对和绝对构型,因此合成样品允许解开各种此类萜类化合物以前未知的立体结构,包括顺式倍半萜烯水合物(33),7-表倍半萜烯(36),倍半萜烯B(37)和环氧倍半萜烯(45)。此外,6的制备也构成了塞得烯(11)和塞多尔(12)的正式全合成。