Chemo- and regioselective synthesis of polysubstituted 2-aminothiophenes by the cyclization of<i>gem</i>-dibromo or<i>gem</i>-dichloroalkenes with β-keto tertiary thioamides
作者:Xuxue Zhang、Chuan Liu、Yupian Deng、Song Cao
DOI:10.1039/d0ob01821j
日期:——
A facile and practical method for the synthesis of 2,3,4-trisubstituted 2-aminothiophenes by the cyclization ofgem-dibromoalkenes orgem-dichloroalkenes with β-keto tertiary thioamides has been developed.
Direct Alkynylation of 3<i>H</i>-Imidazo[4,5-<i>b</i>]pyridines Using <i>gem</i>-Dibromoalkenes as Alkynes Source
作者:Jessy Aziz、Tom Baladi、Sandrine Piguel
DOI:10.1021/acs.joc.6b00406
日期:2016.5.20
C2 direct alkynylation of 3H-imidazo[4,5-b]pyridine derivatives is explored for the first time. Stable and readily available 1,1-dibromo-1-alkenes, electrophilic alkyne precursors, are used as coupling partners. The simple reaction conditions include an inexpensive copper catalyst (CuBr·SMe2 or Cu(OAc)2), a phosphine ligand (DPEphos) and a base (LiOtBu) in 1,4-dioxane at 120 °C. This C–H alkynylation
首次探索了3 H-咪唑并[4,5- b ]吡啶衍生物的C2直接炔基化。稳定且易于获得的1,1-二溴-1-烯烃(亲电炔前体)用作偶联伙伴。简单的反应条件包括:廉价的铜催化剂(CuBr·SMe 2或Cu(OAc)2),膦配体(DPEphos)和1,4-二恶烷中的碱(LiO t Bu)在120°C的条件下。该C-H炔基化方法显露是与各种上两个耦合伙伴取代的兼容:杂芳烃和宝石-dibromoalkenes。该协议可以直接合成各种2-炔基-3 H-咪唑并[4,5- b]吡啶,一种在药物设计中有价值的支架。
A Gold Carbene Manifold to Prepare Fused γ-Lactams by Oxidative Cyclisation of Ynamides
作者:Fernando Sánchez-Cantalejo、Joshua D. Priest、Paul W. Davies
DOI:10.1002/chem.201804378
日期:2018.11.22
in γ‐lactam synthesis but are limited by preferential over‐oxidation to form α‐keto imides. Evaluating the factors that might limit N‐cyclisation pathways led to effective gold‐catalysed conditions that allow access to different fused γ‐lactams on changing the ynamide N‐substituent and accommodate previously incompatible substitution patterns. New and efficient methods for the synthesis of functionalised
Ohmic Heating and Ionic Liquids in Combination for the Indium-Promoted Synthesis of 1-Halo Alkenyl Compounds: Applications to Pd-Catalysed Cross-Coupling Reactions
作者:Raquel G. Soengas、Vera L. M. Silva、Joana Pinto、Humberto Rodríguez-Solla、Artur M. S. Silva
DOI:10.1002/ejoc.201501162
日期:2016.1
We have explored the combination of ohmic heating (ΩH) with ionic liquids for indium-promoted reactions and report herein the indium-promoted dehalogenation of gem-dibromo alkenes and the indium-mediated reductive elimination of chlorohydrins for the synthesis of 1-halo alkenyl derivatives. Heck, Stille, Suzuki, Kumada and Sonogashira couplings of the resulting 1-halo-1-alkenes with appropriate reagents
Rh/bisphosphine−thiourea ligand (ZhaoPhos)‐catalyzed asymmetric hydrogenation of (Z)‐β‐substituted‐β‐boryl‐α,β‐unsaturatedesters was successfully developed, furnishing a variety of chiral β‐borylated carboxylic esters with high yields and excellent enantioselectivities (up to 99% yield and >99% ee). The gram‐scale asymmetric hydrogenation was performed efficiently in the presence of only 0.05 mol%
成功开发了Rh /双膦-硫脲配体(ZhaoPhos)催化的(Z)-β-取代的-β-硼基-α,β-不饱和酯的不对称加氢反应,提供了高收率的多种手性β-硼化羧酸酯优异的对映选择性(高达99%的收率和> 99%的ee)。在仅0.05 mol%(S / C = 2 000)催化剂负载的情况下,可以有效地进行克级不对称氢化反应,并具有完全转化率,99%的收率和99%的ee。此外,加氢产物很容易转化为其他通用的合成中间体,例如(S)-3-羟基-3-苯基丙酸甲酯和(S)-3-(呋喃-2-基)-3-苯基丙酸甲酯。