Proline-catalyzed aldol reactions of acyl cyanides with acetone: an efficient and convenient synthesis of 1,3-diketones
作者:Zongxuan Shen、Bin Li、Lu Wang、Yawen Zhang
DOI:10.1016/j.tetlet.2005.10.036
日期:2005.12
The aldol-type addition of acetonetowards (un)substituted benzoyl, heteroarylcarbonyl or α,β-unsaturated acyl cyanides was efficiently catalyzed by l-proline (30 mol %) to give 2-hydroxy-4-oxo-2-substituted pentanenitriles. Upon the treatment with sodium hydroxide, the adducts transformed to 1,3-diketones in good-to-excellent yield, furnishing an efficient and convenient method for the regioselective
Rh(III)-Catalyzed Cascade Nucleophilic Addition/Annulation of 2-Diazo-1,3-diketones with 1,3-Dicarbonyl Compounds To Access 6,7-Dihydrobenzofuran-4(5<i>H</i>)-ones
A Rh(III)-catalyzed cascade nucleophilic addition/intramolecular annulation of 2-diazo-1,3-diketones with 1,3-dicarbonyl compounds (e.g., 1,3-diketones and β-ketoesters) is achieved to afford 6,7-dihydrobenzofuran-4(5H)-ones in up to 91% yields. Notably, a wide range of substrates and functional groups were well-tolerated under the optimized reaction conditions to give desired products in moderate
2-重氮-1,3-二酮与1,3-二羰基化合物(例如1,3-二酮和β-酮酯)的Rh(III)催化级联亲核加成/分子内环化得到6, 7-dihydrobenzofuran-4(5 H )-ones 的产率高达 91%。值得注意的是,在优化的反应条件下,广泛的底物和官能团具有良好的耐受性,以中等至优异的产率得到所需产物,同时释放出 N 2和 H 2 O 作为副产物。此外,所描述的方法是可扩展的,适用于后期功能化。
Hypervalent iodane mediated reactions of <i>N</i>-acetyl enamines for the synthesis of oxazoles and imidazoles
cyclization of N-acetyl enamines and intermolecular cyclocondensation of enamines and nitriles was investigated. The reaction was performed under mild conditions and gave oxazoles and imidazoles, respectively, in moderate to excellent yields. This transformation exhibits good reactivity, selectivity and functional group tolerance. The selectivity of the intra- or intermolecular reaction is dependent on the
Oxidative [3+3] Annulation of Atropaldehyde Acetals with 1,3‐Bisnucleophiles: An Efficient Method of Constructing Six‐Membered Aromatic Rings, Including Salicylates and Carbazoles
作者:Yanlong Gu、Fengtian Wu、Jian Yang
DOI:10.1002/adsc.201800462
日期:2018.7.16
Alkyl acetoacetates, α‐(indol‐2‐yl)acetate, anilines, 1‐methyl‐1H‐pyrazol‐3‐amine, ethyl 5‐amino‐1H‐pyrazole‐3‐carboxylate, and 3‐amino‐1H‐indazole can all be used as 1,3‐bisnucleophiles in this type of transformation. The established reactions can very efficiently construct six‐membered aromatic rings, including salicylates and carbazoles. A four‐step method of synthesizing the anti‐inflammatory agent