The planar chiral 2‐phospha[3]ferrocenophane I has been shown to be the first efficient nucleophilic organocatalyst for the enantioselective synthesis of cyclopentenylphosphonates, through [3+2] cyclizations between diethyl allenylphosphonate and α,β‐unsaturated ketones. The same catalyst has also been applied to the highly enantioselective [3+2] cyclizations of allenic esters with dibenzylideneacetone
Synthesis and spectroscopic and structural studies of cross-conjugated dienones derived from cyclic ketones and aromatic aldehydes
作者:S. Z. Vatsadze、M. A. Manaenkova、N. V. Sviridenkova、N. V. Zyk、D. P. Krut’ko、A. V. Churakov、M. Yu. Antipin、J. A. K. Howard、H. Lang
DOI:10.1007/s11172-006-0397-6
日期:2006.7
Cross-conjugated dienones were synthesized by the reactions of cyclic ketones with two equivalents of aromatic aldehydes under basic conditions. An NMR spectroscopic study and X-ray diffraction analysis demonstrated that all reaction products are formed as E,E isomers. Spontaneous photochemical trans-cis isomerization of cross-conjugated dienones under the scattered light in solution was observed for
交叉共轭二烯酮是通过环状酮与两当量的芳香醛在碱性条件下反应合成的。NMR 光谱研究和 X 射线衍射分析表明,所有反应产物均以 E、E 异构体的形式形成。首次观察到溶液中散射光下交叉共轭二烯酮的自发光化学反顺异构化。异构化程度主要取决于二烯酮分子中心片段的性质。合成了以前未知的 2,5-双 [(E)-(3-吡啶基) 亚甲基] 环戊酮的光化学 [2+2]-环加成产物,并通过光谱方法和 X 射线衍射进行了表征。在所使用的条件下,仅获得环丁烷加合物的一种异构体。
Aldol condensations of aldehydes and ketones catalyzed by rare earth(III) perfluorooctane sulfonates in fluorous solvents
作者:Wen-Bin Yi、Chun Cai
DOI:10.1016/j.jfluchem.2005.09.004
日期:2005.12
Rare earth(III) perfluorooctane sulfonates (RE(OPf)3) catalyze the efficient aldol condensation of different ketones with various aromatic aldehydes in fluorous solvents without the occurrence of any self-condensations. By simple separation of the fluorous phase containing only catalyst, reaction can be repeated several times.
aromatic aldehydes undergoes crossed aldol condensation with ketones in the presence of a catalytic amount of Yb(OTf) 3 under solvent-free conditions to afford the corresponding α,α'-bis(substitutedbenzylidene)cycloalkanones in excellent yields without occurrence of any side reactions. This method is very general, simple and environmental friendly in contrast with the existing methods, which use many
Solvent-Free Crossed Aldol Condensation of Cyclic Ketones with Aromatic Aldehydes Assisted by Microwave Irradiation
作者:Abbas A. Esmaeili、Mehri Salimi Tabas、Mohammad A. Nasseri、Foad Kazemi
DOI:10.1007/s00706-004-0256-9
日期:2005.4
A fast alumina-promoted crossed aldol-condensation reaction of aldehydes and cyclic ketones under microwave irradiation is described. This process is simple, efficient, and environmentally benign and proceeds in fairly high yield without any self-condensation.