卡罗尔重排反应
(重定向自Carroll反应)
卡罗尔重排反应(英語:Carroll rearrangement),又称卡罗尔-克莱森重排反应,指β-酮酸烯丙酯发生克莱森重排反应产生α-烯丙基-β-酮酸,再经脱羧,得到γ,δ-不饱和酮。[1]
反应机理
反应最初是用碱催化,采用一锅反应,即酯交换(制取β-酮酯)-卡罗尔重排串联进行,需要苛刻条件(乙酸钠,170-240℃)。其机理为烯醇发生的克莱森重排然后脱羧(下图A途径)。现多采用分步方法进行,主要改进包括双负离子法(用二异丙基氨基锂生成双负离子,然后在室温或回流下重排,由此得到的酮酸较易分离)[2][3]以及负载在氯化铝上无溶剂条件下的反应[4]。
1980年辻二郎对此反应作了改进,他用钯(0)作催化剂,经过生成中间体烯丙基正离子/羧酸根负离子有机金属配合物,然后脱羧和烯丙基化,实现了温和条件下的卡罗尔重排(下图B途径)。[5]
![卡罗尔重排的机理](http://images.weserv.nl/?url=//upload.wikimedia.org/wikipedia/commons/c/c8/Carrol_rearrangement_reaction_mechanism.png)
下面用四(三苯基膦)钯(0)催化的实验证实了脱羧一步是在烯丙化前发生。[6]
![脱羧烯丙基化](http://images.weserv.nl/?url=//upload.wikimedia.org/wikipedia/commons/thumb/2/20/Decarboxylative_allylation_mechanistic.png/400px-Decarboxylative_allylation_mechanistic.png)
不对称脱羧烯丙化反应
使用手性配体的不对称卡罗尔重排也有发展。[7] 首个不对称重排由 Burger 等在 2004 年报道,是以三(二亚苄基丙酮)二钯(0)和Trost配体催化:[6]
![烯醇负离子的不对称烯丙化](http://images.weserv.nl/?url=//upload.wikimedia.org/wikipedia/commons/thumb/4/45/AsymmetricCarrol2005.png/400px-AsymmetricCarrol2005.png)
桑野良一等报道了萘酚存在下的卡罗尔重排,反应ee可达88%,但缺点是底物必须要含乙酰氨基基团。[8]
![桑野良一的不对称卡罗尔重排](http://images.weserv.nl/?url=//upload.wikimedia.org/wikipedia/commons/b/b0/AsymmetricCarrolRearrangement.png)
![莫尔的不对称卡罗尔重排](http://images.weserv.nl/?url=//upload.wikimedia.org/wikipedia/commons/thumb/b/b8/DecarboxylativeAllylation.png/400px-DecarboxylativeAllylation.png)
不对称卡罗尔重排也可拓展至烯醇的碳酸酯发生的α-烯丙基化。[10]
![2005年特罗斯特的脱羧烯丙化](http://images.weserv.nl/?url=//upload.wikimedia.org/wikipedia/commons/thumb/b/b5/DecarboxylativeAllylationTrost2005.png/400px-DecarboxylativeAllylationTrost2005.png)
参见
参考资料
- ^ Carroll, M. F. 131. Addition of α,β-unsaturated alcohols to the active methylene group. Part I. The action of ethyl acetoacetate on linalool and geraniol. J. Chem. Soc. 1940: 704–706. doi:10.1039/JR9400000704.
- ^ J. F. Genus, D. D. Peters, J-F. Ding, T. A. Bryson. The Dianion Carroll Rearrangement - A Cyclic Application. Synlett. 1994: 209–210. doi:10.1055/s-1994-22797.
- ^ Stephen R. Wilson, Martyn F. Price. The ester enolate Carroll rearrangement. J. Org. Chem. 1984, 49 (4): 722–725. doi:10.1021/jo00178a036.
- ^ S. I. Pogrebnoi, Y. B. Kalyan, M. Z. Krimer, W. A. Smit. Carrol rearrangement on the surface of chromatographic grade alumina. Tetrahedron Lett. 1987, 28 (41): 4893–4896. doi:10.1016/S0040-4039(00)96654-1.
- ^ Isao Shimizu, Toshiro Yamada and Jiro Tsuji. Palladium-catalyzed rearrangement of allylic esters of acetoacetic acid to give γ,δ-unsaturated methyl ketones. Tetrahedron Letters. 1980, 21 (33): 3199–3202. doi:10.1016/S0040-4039(00)77444-2.
- ^ 6.0 6.1 Erin C. Burger and Jon A. Tunge. Asymmetric Allylic Alkylation of Ketone Enolates: An Asymmetric Claisen Surrogate. Org. Lett. 2004, 6 (22): 4113–4115. doi:10.1021/ol048149t.
- ^ Shu-Li You and Li-Xin Dai. Enantioselective Palladium-Catalyzed Decarboxylative Allylic Alkylations. Angew. Chem. Int. Ed. 2006, 45 (32): 5246–5248. doi:10.1002/anie.200601889.
- ^ Kuwano, R.; Ishida N.; Murakami, M. Asymmetric Carroll rearrangement of allyl α-acetamido-β-ketocarboxylates catalysed by a chiral palladium complex. Chem. Commun. 2005, (31): 3951–3952. doi:10.1039/b505105c..
- ^ Justin T. Mohr, Douglas C. Behenna, Andrew M. Harned, and Brian M. Stoltz. Deracemization of Quaternary Stereocenters by Pd-Catalyzed Enantioconvergent Decarboxylative Allylation of Racemic β-Ketoesters. Angew. Chem. Int. Ed. 2005, 44 (42): 6924–6927. doi:10.1002/anie.200502018.
- ^ Barry M. Trost and Jiayi Xu. Palladium-Catalyzed Asymmetric Allylic α-Alkylation of Acyclic Ketones. J. Am. Chem. Soc. 2005, 127 (49): 17180–17181. doi:10.1021/ja055968f.