Résumé Organocatalyst trityl chloride (Ph3CCl), by in situ formation of trityl carbocation with inherent instability, efficiently promotes the cross-aldol condensation reaction between cycloalkanones and arylaldehydes in solvent-free and homogeneous media to afford α,α′-bis(arylidene)cycloalkanones in high yields. Moreover, an attractive and plausible mechanism based on observations and the literature is proposed for the reaction.
Design, characterization, and use of N,N-diethyl-N-sulfoethanaminium hydrogen sulfate {[Et3N-SO3H]HSO4} as a novel and highly efficient catalyst for preparation of α,α′-bis(arylidene)cycloalkanones
Abstract The aim of this work is to introduce a novel and attractive protic acidic ionic liquid as catalyst for organic synthesis. To achieve this aim, N,N-diethyl-N-sulfoethanaminium hydrogen sulfate [Et3N-SO3H]HSO4} was prepared by reaction of NEt3 with ClSO3H and then with H2SO4. The novel acidic ionic liquid was identified by Fourier-transform infrared (FT-IR), 1H nuclear magnetic resonance (NMR)
摘要 这项工作的目的是引入一种新颖且有吸引力的质子酸性离子液体作为有机合成的催化剂。为了实现该目的,通过使NEt 3与ClSO 3 H,然后与H 2 SO 4反应,制备了N,N-二乙基-N-磺基硫代硫酸氢铵[Et 3 N-SO 3 H] HSO 4 } 。通过傅立叶变换红外光谱(FT-IR),1 H核磁共振(NMR),13鉴定了新型酸性离子液体13 C NMR和质谱。然后在无溶剂条件下,在芳醛与环烷酮的交叉醇醛缩合反应中检测其催化活性,在短时间后以高收率得到α,α'-双(亚芳基)环烷酮。 图形概要
Chemoselective Claisen–Schmidt bis-substitutional condensation catalyzed by an alkoxy-bridged dinuclear Ti(IV) cluster
作者:Yufei Wu、Jie Hou、Yuliang Liu、Mingfu Zhang、Chen-Ho Tung、Yifeng Wang
DOI:10.1016/j.tet.2016.01.055
日期:2016.3
The highly efficient and chemoselective α,α′-bis-substitution of alkanones is important in organic synthesis. Herein, a dimeric titanium cluster, Ti2Cl2(OPri)6·2HOPri (Ti2), is used in the Claisen–Schmidt condensation reaction, for the selectively activation of symmetricalketones containing α,α′-methylene groups and production of α,α′-bis-substituted alkanones in high efficiency and chemoselectivity
Potassium Natural Asphalt Sulfonate (K‐NAS): Synthesis and characterization as a new recyclable solid basic nanocatalyst and its application in the formation of carbon–carbon bonds
In this research, we synthesized and characterized a new heterogeneous basic nanocatalyst and its catalytic application was studied in the Claisen‐Schmidt and Knoevenagel condensations. In order to prepare this nanocatalyst, first, the Iranian natural asphalt was sulfonated with the concentrated sulfuric acid and then, converted to the potassium natural asphalt sulfonate (K‐NAS). In order to characterization
Sulfamic acid: An efficient, cost-effective and green catalyst for crossed-aldol condensation of ketones with aromatic aldehydes under solvent-free
作者:Amin Rostami、Firoz Ahmad-Jangi
DOI:10.1016/j.cclet.2011.03.015
日期:2011.9
Abstract Aromatic aldehydes undergo crossed-aldol condensation with ketones in the presence of catalytic amount of sulfamic acid (SA) to afford the corresponding α , β -unsaturated aldol products under solvent-free conditions in good to high yields at 45–80 °C.