carbon–carbon double bond has been developed from aromatic aldehydes and compounds with active methylene moieties in the presence of catalytic amount of solid sodiumethoxide via mechanochemical approach. This capable process provides a diverse range of homoaryl/heteroaryl/aliphatic acrylates and nitriles in good to excellent yields at short reaction period.Graphical Abstract
syntheses. However, the synthesis of acid–base catalysts is problematic due to the neutralization of acidic and basic groups. This work reports a facial approach to solve this problem via the synthesis of a novel bifunctional polymer using inexpensive materials and easy methods. In this way, at the first step, heterogeneous poly (styrene sulfonic acid‐n‐vinylimidazole) containing pentaerythritol tetr
Phosphine-Catalyzed [4+2] Annulations of 2-Alkylallenoates and Olefins: Synthesis of Multisubstituted Cyclohexenes
作者:Yang S. Tran、Tioga J. Martin、Ohyun Kwon
DOI:10.1002/asia.201100190
日期:2011.8.1
From our investigations on phosphine‐catalyzed [4+2] annulations between α‐alkyl allenoates and activated olefins for the synthesis of cyclohexenes, we discovered a hexamethylphosphorous triamide (HMPT)‐catalyzed [4+2] reaction between α‐alkyl allenoates 1 and arylidene malonates or arylidene cyanoacetates 2 that provides highly functionalized cyclohexenes 3 and 4 in synthetically useful yields (30–89 %)
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。
SYNTHESIS AND ANTI-INFLAMMATORY ACTIVITY OF NEW THIAZOLIDINE-2,4-DIONES, 4-THIOXOTHIAZOLIDINONES AND 2-THIOXOIMIDAZOLIDINONES
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//