Intermolecular and Intramolecular α-Amidoalkylation Reactions Using Bismuth Triflate as the Catalyst
摘要:
Bismuth(III) triflate was found to promote the formation of stable cyclic N-acyliminium species in remarkable catalytic amounts (1 mol %). The alpha-amidoalkylation process seems to be effective in intermolecular and intramolecular manners leading to alpha-substituted lactams and heterocyclic systems containing azacycles, respectively. By comparing our results with those obtained with the classical Lewis acids as catalysts, it was evidenced clearly that the use of bismuth(III) triflate had been efficient for nearly all alpha-acetoxy lactams we used, except for N-acyliminium precursors bearing a sulfur atom. Also, the process seems to be easy, general, and clean, having diastereoselectivity comparable to protocols using classical Lewis acids and resulting in the formation of polyheterocyclic systems in good to excellent yields (64-99% in acetonitrile as solvent).
作者:Liliana Boiaryna、Mohamed Kamal El Mkaddem、Catherine Taillier、Vincent Dalla、Mohamed Othman
DOI:10.1002/chem.201202225
日期:2012.10.29
applied in cascade‐type reactions for the synthesis of different nitrogen‐based compounds. The reactions likely proceed by a new gold‐catalyzed cascade intermolecular α‐amidoalkylation/intramolecular carbocyclization cascade process by unifying both the σ‐ and π‐Lewisacid properties of the gold salts. In the first part of this report we show that the σ‐Lewis acidity of gold(I) and gold(III) could be
Intra- and Intermolecular Alkylation of <i>N</i>,<i>O</i>-Acetals and π-Activated Alcohols Catalyzed by in Situ Generated Acid
作者:Mélanie Hamon、Niall Dickinson、Alice Devineau、David Bolien、Marie-José Tranchant、Catherine Taillier、Ivan Jabin、David C. Harrowven、Richard J. Whitby、A. Ganesan、Vincent Dalla
DOI:10.1021/jo4015886
日期:2014.3.7
allow significant reaction rate enhancements and made possible some challenging reactions such as the α-amidoalkylation of ketones. Studies using flow chemistry confirmed not only that very low concentrations of HCl generated from the solvent were responsible for the reactivity but also that TCE had additional beneficial properties in comparison to other chlorinated solvents such as dichloroethane.
Enolizable Carbonyls and <i>N</i>
,<i>O</i>
-Acetals: A Rational Approach for Room-Temperature Lewis Superacid-Catalyzed Direct α-Amidoalkylation of Ketones and Aldehydes
作者:Bahria Touati、Abderrahman El Bouakher、Catherine Taillier、Raja Ben Othman、Malika Trabelsi-Ayadi、Sylvain Antoniotti、Elisabet Duñach、Vincent Dalla
DOI:10.1002/chem.201504772
日期:2016.4.18
carbonyl donors, that is, ketones and aldehydes with unbiased N,O‐acetals, is described. Sn(NTf2)4 is an optimal catalyst to promote this challenging transformation at low loading and the reaction shows promising scope. A comprehensive and rational evaluation of this reaction has led to the establishment of an empirical scale of nucleophilic reactivity for a broad set of ketones that should be helpful
Synergistic Gold(I)/Trimethylsilyl Catalysis: Efficient Alkynylation of N,O-Acetals and Related Pro-Electrophiles
作者:Malina Michalska、Olivier Songis、Catherine Taillier、Sean P. Bew、Vincent Dalla
DOI:10.1002/adsc.201400169
日期:2014.6.16
This unprecedented manifold opens avenues for developing synergistic silyl‐gold(I)‐catalyzed alkynylation strategies of diverse pro‐electrophiles which were heretofore unattainable, the proof of concept being principally exemplified herein with the first catalytic alkynylation of N,O‐acetals. The reaction proceeds at low catalyst loading, employs mild reaction conditions, is easily scalable, and affords
我们报告了一种独特的机理指导的反应,该反应增强和扩展了目前容易产生的乙炔化金(I)的化学空间。我们的策略利用了具有特定抗衡离子(LAuX – X =三氟甲磺酸或三氟甲磺酸的金(I)嗜碳催化剂的倾向。 )有效激活和去甲硅烷基化三甲基甲硅烷基炔烃,从而原位介导形成等量和催化量的可调强度的甲硅烷基路易斯酸(TMSX)和亲核性金(I)乙炔化物。这种空前的流形为开发各种原亲电子的协同甲硅烷基金(I)催化的炔基化策略开辟了道路,这是迄今为止无法实现的,本文主要以N,O-乙缩醛的首次催化炔基化为例来证明概念验证。该反应在低催化剂负载下进行,采用温和的反应条件,易于扩展,并以良好或优异的产率提供炔丙基内酰胺产物。此外,它完全适用于各种结构和功能的底物,并且还可以扩展到除N,O-乙缩醛以外的其他亲电子试剂。已经进行了控制实验,这些实验强烈支持了我们的双重反应机理建议,与TMSNTf 2相比)和所使用的金抗衡
Towards Simplifying the Chemistry of<i>N</i>-Acyliminium Ions: A One-Pot Protocol for the Preparation of 5-Acetoxy Pyrrolidin-2-ones and 2-Acetoxy<i>N</i>-Alkoxycarbonyl Pyrrolidines from Imides
作者:Vincent Dalla、Fridrich Szemes Jr.、Anthony Fousse、Raja Ben Othman、Till Bousquet、Mohamed Othman
DOI:10.1055/s-2006-926318
日期:——
A new one-step protocol for the synthesis of acetoxy lactams starting from imides has been developed. This method involves regiospecific reduction of the imide with LiEt 3 BH, then capture of the transient lithium alkoxide by acetic anhydride.