Modified Chiral Triazolium Salts for Enantioselective Benzoin Cyclization of Enolizable Keto-Aldehydes: Synthesis of (+)-Sappanone B
摘要:
Asymmetric synthesis of (+)-sappanone B (1), a natural product with a 3-hydroxy chromanone structure, was achieved via enantioselective benzoin cyclization by using a modified Rovis catalyst and triethylamine. This catalyst enabled the successful benzoin cyclization of readily enolizable keto-aldehydes.
[EN] A METHOD OF ACETALIZING AN ALDEHYDE<br/>[FR] PROCÉDÉ D'ACÉTALISATION D'UN ALDÉHYDE
申请人:AGENCY SCIENCE TECH & RES
公开号:WO2013137830A1
公开(公告)日:2013-09-19
A method of acetalizing an aldehyde comprising reacting said aldehyde with an alcohol in the presence of a polymeric catalyst to form an acetal wherein the polymeric catalyst is a mesoporous poly-melamine-formaldehyde polymer.
一种使醛发生缩醛化的方法,包括将所述醛与醇在多孔聚三聚氰胺-甲醛聚合物的催化下反应,形成缩醛。
Mustard Carbonate Analogues as Sustainable Reagents for the Aminoalkylation of Phenols
The nitrogenmustard gas moiety is present as a basic, amine-containing side chain in numerous pharmacophore scaffolds engaging in crucial interactions with targeted biological macromolecules. Herein, a one-pot synthetic approach for the easy introduction of nitrogen mustard-like moieties through dialkyl carbonate chemistry into different phenolic substrates is reported. The scope and limitations of
Tetrabutylammonium Tribromide (TBATB) as An Efficient Generator of HBr for an Efficient Chemoselective Reagent for Acetalization of Carbonyl Compounds
作者:Rangam Gopinath、Sk. Jiaul Haque、Bhisma K. Patel
DOI:10.1021/jo025701o
日期:2002.8.1
Acyclic and cyclic acetals of various carbonyl compounds were obtained in excellent yields under a mild reaction condition in the presence of trialkyl orthoformate and a catalytic amount of tetrabutylammonium tribromide (TBATB) in absolute alcohol. Chemoselective acetalization of an aldehyde in the presence of ketone, unsymmetrical acetal formation, shorter reaction times, mild reaction conditions
Binaphthol-Based Diphosphite Ligands in Asymmetric Nickel-Catalyzed Hydrocyanation of Styrene and 1,3-Cyclohexadiene: Influence of Steric Properties
作者:Jos Wilting、Michèle Janssen、Christian Müller、Martin Lutz、Anthony L. Spek、Dieter Vogt
DOI:10.1002/adsc.200600315
日期:2007.2.5
(R)-binaphthol-based diphosphite ligands with different substituents was prepared and applied in the asymmetric nickel-catalyzedhydrocyanation of styrene and 1,3-cyclohexadiene to investigate the influence of their steric properties. The optimum steric properties for the hydrocyanation reaction lie within a narrow window. With the optimized ligand, hydrocyanation of styrene gave full conversion (Subs/Ni=100)
制备了一系列具有不同取代基的手性(R)-联萘酚基二亚磷酸酯配体,并将其应用于苯乙烯和1,3-环己二烯的不对称镍催化的氢氰化反应中,以研究其空间特性的影响。氢氰化反应的最佳空间特性在狭窄的窗口内。使用优化的配体,苯乙烯进行氢氰化可得到49%ee的完全转化率(Subs / Ni = 100),TON测为600。1,3-环己二烯的氢氰化可得到50%的转化率(Subs / Ni = 500)。优秀的ee为86%。这表明高ee s不仅可用于乙烯基芳烃,而且可用于不对称镍催化的氢氰化反应中的共轭二烯。
The Enantioselective Step in the Nickel-Catalyzed Hydrocyanation of 1,3-Cyclohexadiene
On the basis of deuterium labeling experiments and an equal 1,2-/1,4-product distribution, the reductiveelimination of the product has been established to be the enantioselective step in the nickel-catalyzedhydrocyanation of 1,3-cyclohexadiene. This could be achieved by successfully exploiting the rather unique features of this reaction: identical product formation for 1,2- and 1,4-addition, cis