A versatile difluorovinylation method: Cross-coupling reactions of the 2,2-difluorovinylzinc–TMEDA complex with alkenyl, alkynyl, allyl, and benzyl halides
2-difluorovinylzinc–TMEDA complex was prepared via a deprotonation–transmetallation sequence starting from commercially available 1,1-difluoroethylene. The complex thus formed was successfully applied to transition metal-catalyzed cross-coupling reactions with a wide range of organic halides, which led to the syntheses of 2,2-difluorovinyl compounds. On treatment with the difluorovinylzinc–TMEDA complex in the presence
Room Temperature Carbonylation of (Hetero) Aryl Pentafluorobenzenesulfonates and Triflates using Palladium-Cobalt Bimetallic Catalyst: Dual Role of Cobalt Carbonyl
作者:Jayan T. Joseph、Ayyiliath M. Sajith、Revanna C. Ningegowda、Sheena Shashikanth
DOI:10.1002/adsc.201600736
日期:2017.2.2
method for the carbonylation of (hetero) aryl pentafluorobenzenesulfonates and triflates under exceptionally mild conditions using palladium/dicobalt octacarbonyl [Pd/Co2(CO)8] has been developed. Besides acting as carbon monoxide (CO) source, Co2(CO)8 enhances the reaction rate by accelerating the CO insertion through an in situ generated bimetallic palladium cobalt tetracarbonyl [Pd‐Co(CO)4] complex
已经开发了一种在异常温和的条件下使用钯/二钴八羰基[Pd / Co 2(CO)8 ]对(杂)芳基五氟苯磺酸盐和三氟甲磺酸酯进行羰基化的有效方法。除了充当一氧化碳(CO)源外,Co 2(CO)8还可以通过原位生成的双金属钯四羰基钴[Pd-Co(CO)4)加速CO的插入,从而提高反应速率。] 复杂的。在优化的反应条件下,各种活化和失活的,以及位阻和杂芳族底物的羰基化反应在室温下均能有效进行。生物学上相关的异古瓦汀和拉扎贝米中间体的高化学选择性和改进的合成方法突出了其作为有价值的合成方法的范围。该协议的通用性进一步扩展到其他亲电试剂(溴化物,氯化物和甲苯磺酸盐)。
Palladium(I) Dimer Enabled Extremely Rapid and Chemoselective Alkylation of Aryl Bromides over Triflates and Chlorides in Air
Disclosed herein is the first general chemo- and site-selective alkylation of C-Br bonds in the presence of COTf, C-Cl and other potentially reactive functional groups, using the air-, moisture-, and thermally stable dinuclear PdI catalyst, [Pd(μ-I)PtBu3 ]2 . The bromo-selectivity is independent of the substrate and the relative positioning of the competing reaction sites, and as such fully predictable
chemoselective carbonylation of bromoaryl triflates is reported. The selective C−Br bond versus C−OTf (OTf=triflate) bond functionalization can be remarkably tuned by the combination of the ligand [4,5‐bis(diphenylphosphino)‐9,9‐dimethylxanthene (Xantphos) vs. 1,1′‐bis(diphenylphosphino)ferrocene (DPPF)] and the solvent (toluene vs. DMSO). The respective ligand and solventeffects are rationalized by DFT calculations
报道了钯催化的溴代芳基三氟甲磺酸酯的化学选择性羰基化。选择性C-Br键与C-OTf键(OTf =三氟甲磺酸酯)键的功能可以通过配体的组合进行显着调节[4,5-双(二苯基膦基)-9,9-二甲基x吨(Xantphos)与1,1 '-双(二苯基膦基)二茂铁(DPPF)]和溶剂(甲苯对DMSO)。各自的配体和溶剂效应通过DFT计算得以合理化。相比之下,单齿配体BuPAd 2和t Bu 3 P更倾向于选择性的C-Br键活化,并且对溶剂不敏感。
A robust multifunctional ligand-controlled palladium-catalyzed carbonylation reaction in water
A novel, hydrophilic and recyclable methoxypolyethylene glycol (PEG)-modulated s-triazine-based multifunctional Schiffbase/N,P-ligand L9 was prepared and used in Pd-catalyzed Heck-type carbonylative couplingreactions, affording diverse chalcone derivatives and 1,4-dicarbonyl esters in good yields.