过渡金属催化的单分子片段偶联 (UFC) 定义为通过分子(如 CO 和 CO 2)的挤出以及随后剩余片段的重组形成新化学键的过程。在此,我们报道了一种新的 UFC 反应,该反应涉及钯催化从酰胺中消除异氰酸酯片段,形成碳-碳和碳-杂原子键。通过 X 射线晶体学表征了与催化反应相关的有机金属中间体。这种 UFC 反应能够实现酰胺官能团的后期转化,从而使酰胺能够用作可转换的导向或保护基团。
Deacylative Allylation: Allylic Alkylation via Retro-Claisen Activation
作者:Alexander J. Grenning、Jon A. Tunge
DOI:10.1021/ja205717f
日期:2011.9.21
"deacylative allylation", the coupling partners, an allylic alcohol and a ketone pronucleophile, undergo in situ retro-Claisen activation to generate an allylic acetate and a carbanion. In the presence of palladium, these reactive intermediates undergo catalytic coupling to form a new C-C bond. In comparison to unimolecular decarboxylative allylation, a commonly utilized method for allylation of carbon
本文描述了多种相对不稳定的碳亲核试剂的烯丙基烷基化的新方法。在这个“脱酰基烯丙基化”过程中,偶联伙伴,烯丙醇和酮亲核试剂,进行原位逆克莱森活化以生成烯丙乙酸和碳负离子。在钯的存在下,这些反应性中间体进行催化偶联形成新的 CC 键。与单分子脱羧烯丙基化(一种常用的碳阴离子烯丙基化方法)相比,脱酰基烯丙基化是一种分子间过程。此外,脱酰基烯丙基化允许容易获得的烯丙醇直接偶联。最后,通过快速构建多种 1、
Oxidation of Hindered Allylic C–H Bonds with Applications to the Functionalization of Complex Molecules
作者:Zachary C. Litman、Ankit Sharma、John F. Hartwig
DOI:10.1021/acscatal.6b03648
日期:2017.3.3
oxidation of hindered alkenes to form linear allylic esters. The combination of palladium(II) benzoate, 4,5-diazafluoren-9-one, and benzoquinone catalyzes the mild oxidation of terminalalkenes with tert-butyl benzoyl peroxide as an oxidant in the presence of diverse functional groups. Selective oxidation of terminalalkenes in the presence of trisubstituted and disubstituted alkenes has been achieved
Regio- and Enantioselective Pd-Catalyzed Allylic Alkylation of Ketones through Allyl Enol Carbonates
作者:Barry M. Trost、Jiayi Xu
DOI:10.1021/ja043472c
日期:2005.3.9
ketones occurs asymmetrically in the presence of chiral ligands previously developed in this group. With 2-methylcyclohexanone, asymmetric regioselective alkylation occurs at the more substituted carbon without complications of polyalkylation. Alkylation to create quaternary centers in indanones and benzonabenone occurs in much higher ee than using tin or lithiumenolates. The sense of enantioinduction in
在该组先前开发的手性配体存在下,Pd 催化的烯醇烯丙基碳酸酯重组为烯丙基化酮是不对称的。使用 2-甲基环己酮,不对称区域选择性烷基化发生在更多取代的碳上,而没有多烷基化的并发症。在茚满酮和苯并苯酮中产生四元中心的烷基化发生的 ee 比使用锡或烯醇锂高得多。四氢萘酮中的对映诱导意义与烯醇化锡和锂的例子相反。第一次,在高 ee (78-99%) 的情况下,第三中心的不对称创建发生了。该反应与使用锂或烯醇锡之间的不同结果表明可能涉及不同的机制。
The salt-free nickel-catalysed α-allylation reaction of ketones with allyl alcohol and diallylether
The nickel-catalysed α-allylation of ketones with allylalcohol and diallylether has been performed under neutral conditions. As no base is involved, the products are synthesized without salts as side products. The dppf/Ni(cod)2 catalytic system in MeOH at 80 °C has been shown as the most effective reaction system to afford tetrasubstituted derivatives from various cyclic and acyclic ketones with one
Page 11037. The required annotation for compound 6j in Table 4 was inadvertently missing in our original manuscript. Footnote c has been added to 6j to note that a higher reaction temperature and a longer reaction time were required for this specific substrate, as given below. This information is also included in the revised Supporting Information. The Supporting Information is available free of charge