β-unsaturated N-tosylamides via N-sulfonyl ketenimine formation followed by a probable 1,3-OAc migration ([3,3]-sigmatropic rearrangement). The reaction is very general, allowing all kinds of substitution, including alkyl, aryl (electron-donating, -withdrawing, and -neutral), heteroaryl, and vinylgroups, on the C-terminal of acrylamide. Also, the method affords the products at ambient temperature
Enantioselective Copper-Catalyzed Formal [4 + 2] Cycloaddition of <i>o</i>-Aminophenol Derivatives with Propargylic Esters for Synthesis of Optically Active 3,4-Dihydro-2<i>H</i>-1,4-benzoxazines
作者:Zhen-Ting Liu、Ya-Hui Wang、Fu-Lin Zhu、Xiang-Ping Hu
DOI:10.1021/acs.orglett.6b00322
日期:2016.3.4
The first copper-catalyzed asymmetric formal [4 + 2] cycloaddition of o-aminophenol derivatives with propargylic esters as the bis-electrophilic C2 synthons for the stereoselective construction of chiral 2,3,4-trisubstituted 2H-1,4-benzoxazines bearing an exocyclic double bond has been developed. By using a structurally modified chiralketimineP,N,N-ligand, a wide range of optically active 2H-1,4-benzoxazines
首次铜催化邻氨基苯酚衍生物与炔丙酸酯作为双亲电子C2合成子的不对称[4 + 2]环加成,用于立体选择性地构建手性2,3,4-三取代的2 H -1,4-苯并恶嗪轴承已经开发了环外双键。通过使用结构改性的手性酮亚胺P,N,N-配体,可以高收率和极好的对映选择性(高达97%ee)制备各种光学活性的2 H -1,4-苯并恶嗪。
Enantioconvergent Copper Catalysis: <i>In Situ</i> Generation of the Chiral Phosphorus Ylide and Its Wittig Reactions
highly functionalized chiral P-ylides can be easily synthesized through a copper-catalyzed asymmetric propargylic alkylation reaction from phosphonium salts and racemic propargylic esters. The subsequent Wittig reactions enable the synthesis of versatile alkene building blocks, chiral α-propargylic acrylates, and α-propargylic allenoates, with a wide substrate scope and satisfactory functional group
2-a]pyridines with exclusive regioselectivity in moderate to excellent yields has been developed. This cascade was initiated through propargylation of 2-aminopyridines at pyridine-nitrogen with propargylalcohol derivatives using Cu(II)-Pybox as catalyst and followed by an intramolecular cyclization and isomerization. Besides 2-aminopyridine, less reactive 2-aminopyrimidine, 2-aminopyrazine and 3-aminopyridazine
已经开发出一种高效的级联序列,用于合成2,3-二取代的咪唑并[1,2- a ]吡啶,具有中度到优异的排他选择性。该级联反应是通过使用铜(II)-Pybox作为催化剂在炔丙基醇衍生物上于吡啶氮原子处将2-氨基吡啶进行炔丙基化反应开始的,然后进行分子内环化和异构化。除了2-氨基吡啶,反应性较低的2-氨基嘧啶,2-氨基吡嗪和3-氨基哒嗪也适用于该级联反应。
Stereocontrol in Palladium-Catalyzed Propargylic Substitutions: Kinetic Resolution to give Enantioenriched 1,5-Enynes and Propargyl Acetates
作者:Michael J. Ardolino、Meredith S. Eno、James P. Morken
DOI:10.1002/adsc.201300720
日期:2013.11.25
Kineticresolution during the catalytic allyl-propargyl cross-coupling with chiral starting materials can be accomplished with a chiral Palladium catalyst. These reactions offer ready access to enantiomerically enriched enyne products from simple readily available starting materials.