1-(Hetero)aryl-2,2,2-trichloroethanols are useful key intermediates for the synthesis of various bioactive compounds. Herein, we describe N-heterocyclic carbene (NHC)-coordinated cyclometallated palladium complex (CYP)-catalyzed (hetero)aryl addition of chloral hydrate using (hetero)arylboroxines, providing a new approach to 1-(hetero)aryl-2,2,2-trichloroethanols. Notably, PhS-IPent-CYP which coordinated
Preparation of Quaternary Centers via Nickel-Catalyzed Suzuki–Miyaura Cross-Coupling of Tertiary Sulfones
作者:Zachary T. Ariki、Yuuki Maekawa、Masakazu Nambo、Cathleen M. Crudden
DOI:10.1021/jacs.7b10855
日期:2018.1.10
benzylic and allylic sulfones with arylboroxines. A variety of tertiary sulfones, which can easily be prepared via a deprotonation-alkylation route, were reacted to afford symmetric and unsymmetric quaternary products in good yields. We highlight the use of either BrettPhos or Doyle's phosphines as effective ligands for these challenging desulfonative coupling reactions. The utility of this methodology
我们描述了叔苄基和烯丙基砜与芳基环硼烷的镍催化 Suzuki-Miyaura 交叉偶联的开发。可以通过去质子化-烷基化路线轻松制备的各种叔砜反应以良好的收率提供对称和不对称季产物。我们强调使用 BrettPhos 或 Doyle 膦作为这些具有挑战性的脱磺化偶联反应的有效配体。这种方法的实用性在维生素 D 受体调节剂类似物的简明合成中得到了证明。
Rhodium(I)-Catalyzed Arylation/Dehydroxylation of <i>tert</i>
-Propargylic Alcohols Leading to Tetrasubstituted Allenes
alcohols and arylboroxines under rhodium catalysis. The reaction is assumed to proceed through an arylation/dehydroxylation process, which involves β‐hydroxide elimination of a β‐hydroxy alkenyl‐rhodium intermediate that is generated by regioselective arylrhodation of the tert‐propargylic alcohol. In addition, when enantioenriched propargylic alcohol was used to prepare optically active allene, high
Ligand- and Base-Free Pd(II)-Catalyzed Controlled Switching between Oxidative Heck and Conjugate Addition Reactions
作者:Sarah E. Walker、Julian Boehnke、Pauline E. Glen、Steven Levey、Lisa Patrick、James A. Jordan-Hore、Ai-Lan Lee
DOI:10.1021/ol400539h
日期:2013.4.19
solvent allows controlled and efficient switching between oxidative Heck and conjugateadditionreactions on cyclic Michael acceptor substrates, catalyzed by a cationic Pd(II) catalyst system. Both reactions are ligand- and base-free and tolerant of air and moisture, and the controlled switching sheds light on some of the factors which favor one reaction over the other.
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