Total Syntheses of Multiple Cladiellin Natural Products by Use of a Completely General Strategy
作者:J. Stephen Clark、Raphaëlle Berger、Stewart T. Hayes、Hans Martin Senn、Louis J. Farrugia、Lynne H. Thomas、Angus J. Morrison、Luca Gobbi
DOI:10.1021/jo302542h
日期:2013.1.18
known allylic alcohol (+)-14, which can be prepared in large quantities. The bridged tricyclic core of the cladiellins has been constructed via three ring-forming reactions: (i) an intramolecular reductive cyclization between an aldehyde and an unsaturated ester, mediated by samarium(II) iodide, to form a tetrahydropyranol; (ii) reaction of a metal carbenoid, generated from a diazo ketone, with an ether
从已知的可以大量制备的烯丙醇(+)-14开始,已经完成了10种cladiellin天然产物的对映选择性合成。克拉德林的桥接三环核心是通过三个成环反应构建的:(i)碘化and(II)介导的醛和不饱和酯之间的分子内还原环化反应,形成四氢吡喃醇;(ii)重氮酮产生的金属类胡萝卜素与醚反应生成类似叶立德的中间体,该中间体可重排生成E-或Z-oxabicyclo [6.2.1] -5-undecen-9-one; (iii)Diels-Alder环加成反应,以构建在cladiellins核心结构中发现的第三个环。可以调节重氮成键反应,其中重氮酮转化为桥联双环醚,通过从将铜制成铑催化剂并选择合适的反应条件。从涉及Diels-Alder环加成反应的三步过程中获得的三环产物可以用作高级中间体,以制备各种cladiellin天然产物。