Nickel-Catalyzed Efficient and Practical Suzuki−Miyaura Coupling of Alkenyl and Aryl Carbamates with Aryl Boroxines
作者:Li Xu、Bi-Jie Li、Zhen-Hua Wu、Xing-Yu Lu、Bing-Tao Guan、Bi-Qin Wang、Ke-Qing Zhao、Zhang-Jie Shi
DOI:10.1021/ol9029534
日期:2010.2.19
Suzuki−Miyaura coupling of unactivated alkenyl carbamates is described to construct polysubstituted olefins. The developed process is also suitable for heteroaromatic and even electron-richaromatic carbamates.
allyl–aryl coupling of readily accessible arylboron reagents with a broad range of olefins. Allylic arylation was achieved without the need for prefunctionalized alkenes, and the general Heck-type reactivity between olefins and arenes was not observed. Mechanistic studies indicate that the reaction was enabled through the fast generation of a RhIII–allyl species via undirected C(sp3)–H activation. Moreover
activation. The formation of triene occurs only in the presence of ArB(OH)2. Vinylallene, on the other hand, was shown to be formed by consumption of (ArBO)3 as a first-order reactant. Conditions with sub-stoichiometric BF3·OEt2 gave selectively the vinylallene product, and the reaction is first order in PhB(OH)2. Both C-H activation and transmetalation influence the reaction rate. However, with electron-deficient
Oxidative Coupling of Aryl Boron Reagents with sp<sup>3</sup>-Carbon Nucleophiles: The Enolate Chan-Evans-Lam Reaction
作者:Patrick J. Moon、Heather M. Halperin、Rylan J. Lundgren
DOI:10.1002/anie.201510558
日期:2016.1.26
Reported is a versatile new oxidative method for the arylation of activated methylene species. Under mild reaction conditions (RT to 40 °C), Cu(OTf)2 mediates the selective coupling of functionalized aryl boron species with a variety of stabilized sp3‐nucleophiles. Tertiary malonates and amido esters can be employed as substrates to generate quaternary centers. Complementing either traditional cross‐coupling
报道了一种用于活化的亚甲基物质的芳基化的通用的新氧化方法。在温和的反应条件下(室温至40°C),Cu(OTf)2介导功能化的芳基硼物种与各种稳定的sp 3-亲核试剂的选择性偶联。丙二酸叔丁酯和酰胺基酯可用作底物以生成四元中心。作为传统交叉偶联或S N Ar方案的补充,在卤素亲电试剂(包括芳基溴化物和碘化物)存在下,该转化过程具有化学选择性。带有酰胺基,磺酰基基和膦酰基基团的底物不适合在温和的Hurtley型条件下偶联,是合适的反应伙伴。
Kinetic Resolution and Dynamic Kinetic Resolution of Chromene by Rhodium‐Catalyzed Asymmetric Hydroarylation
作者:Qingjing Yang、Yanbo Wang、Shihui Luo、Jun (Joelle) Wang
DOI:10.1002/anie.201900721
日期:2019.4.8
A highly efficient kineticresolution and dynamickineticresolution of chromene is reported for the first time and they procced by a rhodium‐catalyzed asymmetric hydroarylation pathway. This new approach offers versatile access to various chiral 2,3‐diaryl‐chromanes containing vicinal stereogenic centers, as well as the recovered chiral flavenes, in high yields with excellent ee values (s factor up