asymmetric allylic alkylation

不对称烯丙基烷基化
  • 文章类型: Journal Article
    在这里,描述了甲基氮杂芳烃的Ir催化的不对称烯丙基取代反应。氮杂芳烃如(苯并)噻唑,恶唑,苯并咪唑,吡啶,和(异)喹啉都是耐受的。相应的手性氮杂芳烃衍生物以良好的产率和高对映选择性(高达96%产率和99%ee)获得。Knochel试剂TMPZnBr·LiBr的使用保证了在没有其他活化剂的情况下原位形成苄基亲核试剂。1HNMR研究表明Knochel试剂在该反应中具有双重功能。该方法的合成效用已通过变构蛋白激酶调节剂的简洁的对映选择性合成来展示。
    Herein, an Ir-catalyzed asymmetric allylic substitution reaction of methyl azaarenes is described. Azaarenes such as (benzo)thiazole, oxazole, benzoimidazole, pyridine, and (iso)quinoline are all tolerated. The corresponding chiral azaarene derivatives are obtained in good yields with high enantioselectivity (up to 96 % yield and 99 % ee). The utilization of the Knochel reagent TMPZnBr⋅LiBr warrants the in situ formation of benzylic nucleophiles without additional activating reagents. 1 H NMR studies suggested a two-fold function of the Knochel reagent in this reaction. The synthetic utility of this method has been showcased by a concise enantioselective synthesis of an allosteric protein kinase modulator.
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  • 文章类型: Journal Article
    四元立体中心对于新分子的三维性和增强性质具有重要意义,但是在创建四元立体中心方面的合成挑战极大地阻碍了它们在药物发现中的广泛应用,有机材料设计,和天然产物合成。烯丙基底物的不对称烯丙基烷基化(AAA)已被证明是现代不对称有机催化中具有单个或多个季碳中心的结构骨架的对映选择性形成的强大方法。AAA在构建四合立体中心方面具有一定的优势,包括但不限于轻度反应条件,有效反应速率,新功能组介绍,和碳链长度延长。本文概述了AAA反应应用中的关键考虑因素,并总结了AAA反应在含四元立体中心产物的对映选择性合成中的最新进展。同时,详细讨论了AAA反应,如配体,底物的范围,还提供了转化和一般反应机理。我们希望这次审查能够促进更广泛领域的进一步进展,包括有机合成,不对称催化,C-H活化,和对称药物化学。
    Quaternary stereocenters are of great importance to the three-dimensionality and enhanced properties of new molecules, but the synthetic challenges in creating quaternary stereocenters greatly hinder their wide use in drug discovery, organic material design, and natural product synthesis. The asymmetric allylic alkylation (AAA) of allylic substrates has proven to be a powerful methodology for enantioselective formation of structure skeletons bearing single or more quaternary carbon centers in modern asymmetric organocatalysis. AAA has certain advantages in constructing the tetrasubstituted stereocenters, including but not limited to mild reactive conditions, effective reaction rates, new functional group introduction, and carbon chains length extension. This review outlines the key considerations in the application of AAA reactions and summarizes the recent progress of AAA reactions in the enantioselective synthesis of products containing quaternary stereocenters. Meanwhile, a detailed discussion of the AAA reactions such as ligands, scope of substrates, transformations and the general reaction mechanisms is also provided. We hope this review could stimulate further advances in much broader areas, including organic synthesis, asymmetric catalysis, C-H activation, and symmetrical pharmaceutical chemistry.
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  • 文章类型: Journal Article
    An efficient dual catalytic system composed of a chiral primary amine and a palladium complex was developed to promote the direct asymmetric allylic alkylation (AAA) of β-ketocarbonyl compounds. In particular, the synergistic dual catalytic system enabled the AAA reaction of challenging acyclic aliphatic ketones, such as β-ketocarbonyl compounds and 1,3-diketones.
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