Organocatalyzed Cascade Aza-Michael/Michael Addition for the Asymmetric Construction of Highly Functionalized Spiropyrazolone Tetrahydroquinolines
作者:Jun-Hua Li、Da-Ming Du
DOI:10.1002/asia.201402706
日期:2014.11
An organocatalyzed diastereo‐ and enantioselectivecascadeaza‐Michael/Michaeladdition of 2‐tosylaminoenones to unsaturated pyrazolones has been developed to afford novel chiral spiropyrazolone tetrahydroquinolines containing three contiguous stereocenters. This cascade reaction proceeded well with 2 mol % chiral bifunctional tertiary amine squaramide catalyst to give the desired products in excellent
Phosphine-Catalyzed Cascade Reaction of Unsaturated Pyrazolones with Alkyne Derivatives: Efficient Synthesis of Pyrano[2,3-<i>c</i>]pyrazoles and Spiro-cyclopentanone-pyrazolones
作者:Jun-Hua Li、Da-Ming Du
DOI:10.1002/adsc.201500675
日期:2015.12.14
triphenylphosphine-catalyzed cascadereaction of unsaturatedpyrazolones with dialkyl acetylenedicarboxylates or but-3-yn-2-one to synthesize the bioactive pyrano[2,3-c]pyrazoles in moderate to excellent yields has been developed. Meanwhile, spiro-cyclopentanone-pyrazolones were also first constructed by the triphenylphosphine-catalyzed cascadereaction of unsaturatedpyrazolones with 4-phenylbut-3-yn-2-one
已开发出三苯膦催化不饱和吡唑酮与乙炔二羧酸二烷基酯或3-yn-2-one的级联反应,以中等至优异的产率合成生物活性吡喃并[2,3- c ]吡唑。同时,还通过三苯基膦催化的不饱和吡唑啉酮与4-苯基丁-3-yn-2-one的级联反应以中等至良好的收率构建了螺-环戊酮-吡唑啉酮。
Enantioselective Synthesis of<i>N</i>-Phenyl-dihydropyrano[2,3-<i>c</i>]pyrazoles via Cascade Michael Addition/Thorpe-Ziegler Type Cyclization Catalyzed by a Chiral Squaramide
作者:Junhua Li、Daming Du
DOI:10.1002/cjoc.201400829
日期:2015.4
Enantioselectivesynthesis of biologically active dihydropyrano[2,3‐c]pyrazoles has been achieved through a squaramide‐catalysed Michaeladdition/Thorpe‐Ziegler typecyclizationcascade reaction between arylidenepyrazolones and malononitrile. A series of optically active dihydropyano[2,3‐c]pyrazoles were obtained in excellent yields (up to 99%) and moderate to good enantioselectivities (up to 79% ee)
具有生物活性的二氢吡喃并[2,3- c ]吡唑的对映选择性合成是通过对苯二酚吡唑并酮和丙二腈之间的方胺催化的Michael加成反应/ Thorpe-Ziegler型环化级联反应实现的。在温和的反应条件下,以优异的收率(高达99%)和中等至良好的对映选择性(高达79%ee)获得了一系列光学活性的二氢吡喃并[2,3- c ]吡唑。
Highly diastereoselective synthesis of spiro[tetrahydrothiophene-3,3′-pyrazol] with an all-carbon quaternary stereocenter via [3 + 2] cascade Michael/Michael cyclization catalyzed by DABCO
ABSTRACT The diastereoselective formation of spiro[tetrahydro thiophene-3,3′-pyrazol] derivatives has been achieved via a Michael/Michael cyclization reaction. The reaction was performed using trans-ethyl 4-mercapto-2-butenoate 1 with various 4-benzylidene-5-methyl-2-phenylpyrazolones 2 catalyzed by 1,4-diazabicyclo[2.2.2]octane (DABCO) in toluene at 0 °C. The reaction proceeds rapidly and affords
An asymmetric formal one-pot reaction of 4-hydroxycoumarins with unsaturated pyrazolones has been developed by merging a chiral bifunctional organocatalyst with molecular iodine, which furnished a series of optically active spiro[dihydrofurocoumarin/pyrazolone] heterocycles with spiro quaternary stereogenic centers in moderate to excellent yields (up to 99%) with excellent diastereoselectivities (up