卡罗尔重排反应
卡罗尔重排反应(英语: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]
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]
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]
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.