Enantioselective ene reaction of cyclopentadiene and α,β-enals catalyzed by a diphenylprolinol silyl ether
Enantioselective ene reaction of cyclopentadiene and α,β-enals catalyzed by a diphenylprolinol silyl ether
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DOI：
10.1002/anie.200602925
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发表时间：
2006-01-01
影响因子：
16.6
通讯作者：
Hayashi, Yujiro
中科院分区：
文献类型：
--
作者：
Gotoh, Hiroaki;Masui, Ryouhei;Hayashi, Yujiro
烯反应是一种有用的碳-碳键形成反应。[1]虽然已经报道了几个优秀的不对称羰基烯反应，[2]还没有描述过以烯烃为亲烯体的高对映选择性分子间烯反应，只有Narasaka等人的两篇关于分子内反应的报道。（包括本作者之一）[3]和Desimoni等人。[4]另一方面，有机催化反应的范围正在迅速扩大，近年来开发了许多新的手性有机催化剂。[5]Jørgensen及其同事[6]和我们的小组[7]都独立开发了一种二芳基脯氨醇甲硅烷基醚作为有效的有机催化剂。[8]在我们将这种催化剂应用于已知由有机催化介导的不对称Diels-Alder反应[9]期间，我们发现环戊二烯和α，β-烯醛的反应没有得到Diels-Alder产物，而是得到具有高对映选择性的烯产物，如本文所述。这种行为似乎是非常不寻常的。自从1928年发现了机械相关的狄尔斯-阿尔德反应以来，[10]环戊二烯经常被用作最通用的二烯之一。[11]然而，据我们所知，还没有报道它在烯反应中作为烯组分，尽管环戊二烯与苄叉丙酮或苄叉苯乙酮反应得到1，2-二氢并环戊二烯，其中迈克尔型加合物被假定为中间体，已经报道。[12个]第一章
The ene reaction is a useful carbon–carbon bond-forming reaction.[1] Although several excellent asymmetric carbonyl ene reactions have been reported,[2] no highly enantioselective intermolecular ene reactions with an alkene as the enophile have been described yet, with only two reports on the intramolecular reaction by Narasaka et al.(including one of the present authors)[3] and Desimoni et al.[4] On the other hand, the scope of organocatalysis-mediated reactions is expanding very rapidly, and many new chiral organocatalysts have been developed in recent years.[5] Jørgensen and co-workers [6] and our group [7] both independently developed a diarylprolinol silyl ether as an effective organocatalyst.[8] During our application of this catalyst to the asymmetric Diels–Alder reaction, which is known to be mediated by organocatalysis,[9] we found that the reaction of cyclopentadiene and α, β-enals afforded not the Diels–Alder product, but rather the ene product with high enantioselectivity, as described herein. This behavior appears to be highly unusual. Since the discovery of the mechanistically related Diels–Alder reaction in 1928,[10] cyclopentadiene has often been employed as one of the most versatile dienes.[11] However, as far as we are aware there have been no reports of it acting as the ene component in an ene reaction, though the reaction of cyclopentadiene with benzalacetone or benzalacetophenone to give 1, 2-dihydropentalenes, in which a Michael-type adduct is postulated as an intermediate, has been reported.[12]