A highly enantioselective isocyanide-based multicomponent reaction catalyzed by a chiral N,N′-dioxide/MgII complex was reported. A wide range of substrates were tolerated in this reaction, including alkyl- and aryl-substituted isocyanides with alkylidene malonates and various phenols, affording the corresponding phenoxyimidate products in good to excellent yields (up to 94% yield) with good to excellent
报道了一种由手性N , N ' -二氧化物 / Mg II 配合物催化的高对映选择性异氰化物基多组分反应。在该反应中可以耐受多种底物,包括烷基和芳基取代的异氰化物与亚烷基丙二酸酯和各种酚,以良好至极好的产率(高达 94% 的产率)提供相应的苯氧基亚胺酸酯产物,具有良好至极好的对映选择性(高达到 95.5: 4.5 er)。提出了催化循环和过渡态来合理化反应过程和对映控制。
Use of isopropyl alcohol as a solvent in Ti(O-i-Pr)4-catalyzed Knöevenagel reactions
Knöevenagelreactions of aldehydes and ketones with malononitrile, isopropyl cyanoacetate and diisopropyl malonate catalyzed by Ti(O-i-Pr)4 proceeded smoothly in i-PrOH to give the corresponding reaction products in good to high yield. 3-Substituted coumarins were prepared by the present method.
Stereospecific Copper(II)-Catalyzed Tandem Ring Opening/Oxidative Alkylation of Donor–Acceptor Cyclopropanes with Hydrazones: Synthesis of Tetrahydropyridazines
Aerobic copper(II)-catalyzed tandem ringopening and oxidative C–H alkylation of donor–acceptorcyclopropanes with bisaryl hydrazones is accomplished to produce tetrahydropyridazines, in which copper(II) plays dual role as a Lewis acid as well as redox catalyst. The reaction is stereospecific, and optically active cyclopropanes can be reacted with high optical purities (89–98% enantiomeric excess)
Mechanochemical Copper‐Catalyzed Asymmetric Michael‐Type Friedel–Crafts Alkylation of Indoles with Arylidene Malonates
作者:Plamena Staleva、José G. Hernández、Carsten Bolm
DOI:10.1002/chem.201901826
日期:2019.7.11
asymmetric Michael‐type Friedel–Crafts alkylation of indoles with arylidene malonates was developed. The reaction proceeds under ambient atmosphere using a chiral bis(oxazoline)copper catalyst in a mixer mill. Under these reaction conditions nineteen 3‐substituted indolederivatives were synthesized in good to excellent yields (up to 98 %), and with good enantioselectivities (up to 91:9 e.r.) after short milling
Enantiocontrolled Synthesis of β‐Branched α‐Amino Acids by Using Cu
<sup>I</sup>
‐Catalyzed 1,4‐Addition of Glycine Imines to β‐Substituted
<i>gem</i>
‐Diactivated Olefins
作者:Jorge Hernández‐Toribio、Ramón Gómez Arrayás、Juan C. Carretero
DOI:10.1002/chem.201100374
日期:2011.5.27
Branching out! The catalytic asymmetric conjugate addition of glycinate Schiff bases to β‐substituted gem‐diactivated Michael acceptors under proton transfer conditions gives a variety of β‐branched α‐amino acids (see scheme; Dpm=diphenylmethylene, EWG=electron‐withdrawing group) with excellent levels of diastereo‐ (typically syn/anti >90:10) and enantiocontrol (90–99 % ee).
分支出!催化不对称共轭加成的甘氨酸Schiff碱至β -取代的宝石-diactivated质子转移条件下迈克尔受体给出的各种β-α支链氨基酸(参见方案; DPM =二苯基亚甲基,EWG =吸电子基团)具有优良的非对映体水平(通常是syn / anti > 90:10)和对映体控制(90–99% ee)。