Visible light-mediated oxidative decarboxylation of arylacetic acids into benzyl radicals: addition to electron-deficient alkenes by using photoredox catalysts
arylacetic acids bearing an amino group at the para-position in the benzene ring with alkenes in the presence of a catalytic amount of transition metal polypyridyl complexes as photocatalysts under visible light illumination proceed smoothly to give the corresponding benzylated products via oxidative decarboxylation in good to high yields.
Base-free Knoevenagel condensation catalyzed by copper metal surfaces
作者:E. M. Schneider、M. Zeltner、N. Kränzlin、R. N. Grass、W. J. Stark
DOI:10.1039/c5cc02541a
日期:——
Commercially available dendritic copper powder catalyses Knoevenagel condensation under mild conditions with high isolated yields obtained by filtration of Cu and subsequent recrystallization.
Efficient Asymmetric Synthesis of 4H-Chromene Derivatives through a Tandem Michael Addition-Cyclization Reaction Catalyzed by a Salen-Cobalt(II) Complex
The asymmetricsynthesis of 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromene derivatives was achieved through a tandemMichaeladdition-cyclizationreaction of easily available cyclohexane-1,3-dione and ethyl 2-cyano-3-phenylacrylates. Moderate to good yields (up to 81 %) and high enantioselectivities (up to 89 % ee) were obtained with a chiral salen-cobalt(II) complex. This process was air tolerant and
2-氨基-5-氧代-5,6,7,8-四氢-4H-色烯衍生物的不对称合成是通过容易获得的环己烷-1,3-二酮和乙基2-的迈克尔加成环化反应实现的。氰基-3-苯基丙烯酸酯。使用手性 salen-钴 (II) 复合物获得了中等至良好的产率(高达 81%)和高对映选择性(高达 89% ee)。该过程具有耐空气性且易于执行,为合成手性 4H-色烯衍生物提供了一种有效的方法。
MOF derived mesoporous K-ZrO<sub>2</sub> with enhanced basic catalytic performance for Knoevenagel condensations
作者:Peng Wang、Jian Feng、Yupei Zhao、Sai Gu、Jian Liu
DOI:10.1039/c7ra12378g
日期:——
heat-treatment process can act both as mesoporous templates and base-resistant reinforcement for zirconia. The resultant mesoporous K-ZrO2 catalysts with high surface area show excellent catalytic performance in Knoevenagelcondensations, especially for substrates with large molecular size. The mesoporous KZ also show enhanced activity when compared to KZ synthesized from traditional zirconium hydroxides. To the
compounds. In particular thiazolidines are known to show anti-inflammatory activity. With reference to this, synthesis of some 5-benzylidene-thioxoimidazolidinones and thioxothiazolidinones substituted at the position 3 by a benzyl (or phenacyl) group, were reported in previous papers [3-5]. Synthesis and physicochemical data of new 5-benzylidene-3-(4-chlorobenzyl)thiazolidine-2,4-diones 8-10 or 5-(l//