Enantioselective synthesis of α-alkylidene-γ-butyrolactones: intramolecular Rauhut-Currier reaction promoted by acid/base organocatalysts.
Enantioselective synthesis of α-alkylidene-γ-butyrolactones: intramolecular Rauhut-Currier reaction promoted by acid/base organocatalysts.
复制标题
DOI：
10.1002/anie.201201542
复制
发表时间：
2012-05
影响因子：
--
通讯作者：
S. Takizawa;Tue Minh‐Nhat Nguyen;André Grossmann;D. Enders;H. Sasai
中科院分区：
文献类型：
--
作者：
S. Takizawa;Tue Minh‐Nhat Nguyen;André Grossmann;D. Enders;H. Sasai
在十多年的时间里，对映选择性有机催化已发展成为合成有机化学中金属催化和生物催化的补充方法。 [1]在这些成就中，使用手性有机催化剂的碳-碳键形成反应在高度选择性地创建用于天然产物合成的有用骨架方面发挥着突出的作用。 [2]众所周知，Rauhut-Currier (RC) 反应可以通过两种不同的 a, b-不饱和羰基化合物的偶联提供容易获得 a-取代烯酮的途径，其中一种化合物充当潜在的烯醇化物。 [3, 4] 迄今为止，已经开发出基于非手性催化的有吸引力的系统用于 RC 过程，[5] 尽管已经报道了一些合成上有用的对映选择性 RC 转化的例子。对映选择性 RC 反应的首次突破由 Aroyan 和 Miller [6a] 于 2007 年报道，Gladysz、[6b] Christmann、[6c] 和 Wu 等小组的进一步贡献。[6d] 这些小组成功开发了双（烯酮）或烯醛-烯酮的对映选择性环异构化。 [6]与此同时，Gu、Xiao 和同事将此反应扩展到硝基烯烃。[7] Scheidt 等人 [8a] 以及 Shi 等人 [8b] 提出了 Sc (OTf) 3/(R, R)-Ph-Pybox 或 b-ICD 催化的硅氧基联烯和联烯酸酯的分子间 RC 反应。通过对映选择性 RC 反应高度选择性地构建复杂框架一直是不对称合成化学中的一个挑战。我们设想，通过 RC 反应可以从现成材料中轻松获得前手性二烯酮 2 的去对称化，作为制备 a-亚烷基-g-丁内酯 1 的直接且原子经济的方法（图 1）。 [9] α-亚烷基-g-丁内酯骨架为
In a little over a decade, enantioselective organocatalysis has been developed as a complementary methodology to metaland biocatalysis in synthetic organic chemistry.[1] Among the achievements, carbon–carbon bond-forming reactions using chiral organocatalysts play an outstanding role in enabling the highly selective creation of useful skeletons for natural product synthesis.[2] The Rauhut–Currier (RC) reaction is known to provide ready access to a-substituted enones through the coupling of two different a, b-unsaturated carbonyl compounds, one of which serves as a latent enolate.[3, 4] To date, attractive systems based on achiral catalysis have been developed for the RC process,[5] although few examples of synthetically useful enantioselective RC transformations have been reported. The first breakthrough in the enantioselective RC reaction was reported by Aroyan and Miller [6a] in 2007 with further contributions by the groups of Gladysz,[6b] Christmann,[6c] and Wu.[6d] These groups succeeded in the development of the enantioselective cycloisomerization of bis (enones) or enal-enones.[6] Meanwhile, Gu, Xiao, and coworkers extended this reaction to nitroolefins.[7] Scheidt and co-workers [8a] and Shi and co-workers [8b] presented the intermolecular RC reaction of silyloxyallenes and allenoates catalyzed by Sc (OTf) 3/(R, R)-Ph-Pybox or b-ICD. Highly selective construction of complex frameworks through the enantioselective RC reaction has been a challenge in asymmetric synthetic chemistry.We envisioned that the desymmetrization of the prochiral dienones 2, which are easily accessible from readily available materials, by the RC reaction as a straightforward and atomeconomical way to prepare a-alkylidene-g-butyrolactones 1 (Figure 1).[9] The a-alkylidene-g-butyrolactone skeleton is