Synthesis of bridged azabicyclic structures via ring-closing olefin metathesis
Synthesis of bridged azabicyclic structures via ring-closing olefin metathesis
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DOI：
10.1021/jo0349936
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发表时间：
2003-11-14
影响因子：
3.6
通讯作者：
Martin, SF
中科院分区：
文献类型：
--
作者：
Neipp, CE;Martin, SF
提出了一种新的合成氮杂双环[m.n.1]烯烃（m = 3-5; n = 3，2）的方法，该方法涉及顺式-2，6-二烯基-N-酰基哌啶衍生物的闭环复分解（RCM）反应。所需的2，6-二烯基哌啶可以由戊二酰亚胺（11）经六步或由4-甲氧基吡啶（25）经三步容易地制备。在建立该方法的实际效用的一个实施例中，制备了官能化的8-氮杂双环[3.2.1]辛烷32，其是用于合成各种托烷生物碱的潜在中间体。此外，已经开发了用于构建桥连四氢-β-咔啉环系统5的新路线，其特征在于烯炔45的闭环复分解以构建46中的桥环。这个简明的路线46也具有潜在的一般和有用的程序，从酯功能的一步制备末端炔。46中的乙烯基选择性氧化得到不饱和醛47，它可作为合成几种Sarpagine生物碱的有用中间体。
A new strategy for the facile synthesis of azabicyclo[m.n.1]alkenes (m = 3-5; n = 3, 2) has been developed that involves the ring-closing metathesis (RCM) reaction of cis-2,6-dialkenyl-N-acyl piperidine derivatives. The requisite 2,6-dialkenylpiperidines may be readily prepared in six steps starting from glutarimide (11) or three steps from 4-methoxypyridine (25). In one example that establishes the practical utility of the procedure, the functionalized 8-azabicyclo [3.2.1] octane 32, which is a potential intermediate for the syntheses of various tropane alkaloids, was prepared. Additionally, a new route for the construction of the bridged tetrahydro-beta-carboline ring system 5 has been developed that features the ring-closing metathesis of the enyne 45 to construct the bridging ring in 46. This concise route to 46 also features a potentially general and useful procedure for the one-step preparation of a terminal alkyne from an ester function. Selective oxidation of the vinyl group in 46 afforded the unsaturated aldehyde 47, which may serve as a useful intermediate in syntheses of several Sarpagine alkaloids.