Methylene-bridged bis(imidazoline)-derived 2-oxopyrimidinium salts as catalysts for asymmetric Michael reactions.
Methylene-bridged bis(imidazoline)-derived 2-oxopyrimidinium salts as catalysts for asymmetric Michael reactions.
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DOI：
10.1002/anie.201300614
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发表时间：
2013-07-01
影响因子：
16.6
通讯作者：
Hii, King Kuok (Mimi)
中科院分区：
文献类型：
--
作者：
Sheshenev, Andrey E.;Boltukhina, Ekaterina V.;White, Andrew J. P.;Hii, King Kuok (Mimi)
关键词：
甘氨酸衍生亚胺酯(1)与Michael受体的共轭加成可以产生具有三个连续立体中心的高功能化分子（方案1），这是一种有吸引力的策略，可以在没有副产物的情况下一步从非手性前体组装分子复杂性。目前，非金属相转移催化剂（ptc）和有机催化剂（[2]）在这些反应中得到了很好的应用Corey等人首次报道了在n -烷基化辛可尼定盐存在下，1与丙烯酸酯和烯酮的共轭加成具有显著的对映选择性（> 90% ee）随后，其他改性金鸡纳生物碱[5]和新的催化剂扩大了反应的范围，这些催化剂主要由酒石酸盐衍生的季二（铵）和n -螺铵基团、[6]轴手性1,1 ' -联芳基单元、[5f， 7]肌醇衍生的冠醚、[8]和杯状[4]芳烃氨基酸[9]组成使用这些ph中性催化剂需要强碱来生成亲核试剂，因此需要非常低的温度（通常为À40至À788C）来抑制竞争性反应。
Conjugate addition of glycine-derived imine esters (1) to Michael acceptors can generate highly functionalized molecules with up to three contiguous stereogenic centers (Scheme 1), which is an attractive strategy for assembling molecular complexity from achiral precursors in a single step without byproducts.[1]Presently, nonmetal-based phase-transfer catalysts (PTCs) and organocatalysts [2] have been deployed to great effect for these reactions.[3] Corey et al. first reported the conjugate addition of 1 to acrylates and enones with notable enantioselectivity (> 90% ee) in the presence of an N-alkylated cinchonidine salt.[4] Subsequently, the scope of the reaction was expanded with other modified cinchona alkaloids [5] as well as new catalysts, comprising largely of quaternary bis (ammonium) and N-spiro ammonium moieties derived from tartrates,[6] axially-chiral 1, 1’-biaryl units,[5f, 7] inositol-derived crown ethers,[8] and a calix [4] arene amino acid.[9] The use of these pH-neutral catalysts requires strong bases to generate the nucleophile, thus very low temperatures (typically À40 to À788C) were necessary to suppress competitive reactions.
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影响因子：
1.8
作者：
Corey, EJ;Noe, MC;Xu, F
通讯作者：
Xu, F
影响因子：
3.6
作者：
Ryoda, Akemi;Yajima, Nana;Ishikawa, Tsutomu
通讯作者：
Ishikawa, Tsutomu
影响因子：
0.6
作者：
Arai, S;Takahashi, F;Nishida, A
通讯作者：
Nishida, A
影响因子：
0.9
作者：
Chinchilla, R;Mazón, P;Yus, M
通讯作者：
Yus, M
影响因子：
2.6
作者：
Ramalingam, Balamurugan;Neuburger, Markus;Pfaltz, Andreas
通讯作者：
Pfaltz, Andreas