Enantioselective Organo-SOMO Cascade Cycloadditions: A Rapid Approach to Molecular Complexity from Simple Aldehydes and Olefins
作者:Nathan T. Jui、Esther C. Y. Lee、David W. C. MacMillan
DOI:10.1021/ja104313x
日期:2010.7.28
radical-mediated (4 + 2) coupling reaction of aldehydes and conjugated olefins has been achieved through asymmetric SOMO-catalysis. A radical-polar crossover mechanism is proposed wherein olefin addition to a transient enamine radical cation and oxidation of the resulting radical furnishes a cation which is vulnerable to nucleophilic addition. A range of aromatic aldehydes are shown to couple with styrenes and
Sonogashira Reaction of Aryl and Heteroaryl Halides with Terminal Alkynes Catalyzed by a Highly Efficient and Recyclable Nanosized MCM-41 Anchored Palladium Bipyridyl Complex
A heterogeneous catalyst, nanosized MCM-41-Pd, was used to catalyze the Sonogashira coupling of aryl and heteroaryl halides with terminal alkynes in the presence of CuI and triphenylphosphine. The coupling products were obtained in high yields using low Pd loadings to 0.01 mol%, and the nanosized MCM-41-Pd catalyst was recovered by centrifugation of the reaction solution and re-used in further runs without significant loss of reactivity.
Fe(OTf) 3 -catalyzed tandem Meyer-Schuster rearrangement/intermolecular hydroamination of 3-aryl propargyl alcohols for the synthesis of acyclic β-Aminoketones
作者:Ruiheng Tao、Yan Yin、Yongbin Duan、Yuxing Sun、Yue Sun、Fengkai Cheng、Jinpeng Pan、Cheng Lu、Yuan Wang
DOI:10.1016/j.tet.2017.02.030
日期:2017.3
Fe(OTf)3-catalyzed synthesis of acyclic β-aminoketones from 3-aryl propargyl alcohols and nitrogen nucleophiles were investigated. Results showed that propargyl alcohols without bulky groups α to the hydroxyl group underwent the transformation smoothly. Sulphonamides exhibited the higher reactivity than amides as the nitrogen nucleophiles and the transformation of acyclic β-aminoketones were finished
Benzannulation of Substituted 3-Alkoxycarbonylhex-3-en-5-ynoic Acids: A New Route to 4-Substituted 3,5-Dihydroxybenzoic Acids Derivatives
作者:Stefano Serra、Claudio Fuganti
DOI:10.1055/s-2002-34212
日期:——
A new regioselective pathway to 4-substituted 3,5-dihydroxybenzoic acids derivatives is described here. According to this procedure substituted propargylic aldehydes are converted into substituted 3-alkoxycarbonylhex-3-en-5-ynoic acids, which are in turn, treated with acetic anhydride in the presence of sodium acetate to give the substituted benzoic acids derivatives. The aromatic moiety constructed
sulfur nucleophiles is reported. The investigation of the reaction substrates scope indicated that primary 3-aryl propargyl alcohols and thiols underwent the transformation smoothly. The reaction probably proceeded a Bi(OTf)3-catalyzed tandem Meyer-Schuster rearrangement of 3-aryl propargyl alcohol, followed by a thiol Michael conjugateaddition of thiols to in situ generated α, β-unsaturated ketones