New strategies for organic catalysis: The first enantioselective organocatalytic 1,3-dipolar cycloaddition
New strategies for organic catalysis: The first enantioselective organocatalytic 1,3-dipolar cycloaddition
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DOI：
10.1021/ja005517p
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发表时间：
2000-10-11
影响因子：
15
通讯作者：
MacMillan, DWC
中科院分区：
文献类型：
--
作者：
Jen, WS;Wiener, JJM;MacMillan, DWC
我们的实验室一直致力于设计广泛有用的新策略，利用有机化学品作为反应催化剂的对映选择性催化。在我们最近的研究中，我们报道了使用亚胺离子与手性咪唑烷酮1（eq 1）的可逆形成的R，β-不饱和醛的LUMO降低活化是用于开发对映选择性有机催化Diels-Alder反应（eq 2）的有价值的平台。1在这项工作中，我们揭示了这种催化策略也适用于硝酮和R，β-不饱和醛之间的[3+ 2]环加成反应，以提供异恶唑烷（等式3），用于构建生物学上重要的氨基酸，β-内酰胺，氨基碳水化合物和生物碱的有用的配体。2据我们所知，这是有机催化的1，3-偶极环加成反应的第一个例子。3此外，这项研究进一步证明，手性胺可以作为一系列的不对称催化剂的转化，传统上利用金属salts.Given的操作和经济的优势与有机催化，我们最近试图进一步证明我们的亚胺活化策略的价值，通过开发的反应变体，目前无法使用刘易斯酸催化剂。在这方面，已经确定，
Our laboratory has been engaged in the design of broadly useful new strategies for enantioselective catalysis that utilize organic chemicals as reaction catalysts. In our recent study, we reported that the LUMO-lowering activation of R, β-unsaturated aldehydes using the reversible formation of iminium ions with chiral imidazolidinones 1 (eq 1) is a valuable platform for the development of enantioselective organocatalytic Diels-Alder reactions (eq 2). 1 In this work, we reveal that this catalytic strategy is also amenable to [3+ 2] cycloadditions between nitrones and R, β-unsaturated aldehydes to provide isoxazolidines (eq 3), useful synthons for the construction of biologically important amino acids, β-lactams, amino carbohydrates, and alkaloids. 2 To our knowledge, this is the first example of an organocatalytic 1, 3-dipolar cycloaddition. 3 Moreover, this study further documents that chiral amines can be employed as asymmetric catalysts for a range of transformations that traditionally utilize metal salts.Given the operational and economical advantages associated with organocatalysis, we recently sought to further demonstrate the value of our iminium-activation strategy through the development of reaction variants that are currently unavailable using Lewis acid catalysts. In this context, it has been established that