New Efficient Organic Activators for Highly Enantioselective Reduction of Aromatic Ketones by Trichlorosilane
摘要:
Aryl ketones were reduced to the corresponding alcohols with excellent enantioselectivity (up to 99.7% ee) by Cl3SiH in the presence of a catalytic amount of N-formyl-alpha '-(2,4,6-triethylphenyl)-L-proline as an activator. Both carboxyl group at the alpha-position of the activator and 2,4,6-triethylphenyl group at the alpha '-position were critical for the high enantioselectivity.
Cross Coupling of Acyl and Aminyl Radicals: Direct Synthesis of Amides Catalyzed by Bu4NI with TBHP as an Oxidant
作者:Zhaojun Liu、Jie Zhang、Shulin Chen、Erbo Shi、Yuan Xu、Xiaobing Wan
DOI:10.1002/anie.201108763
日期:2012.3.26
A radical solution: A Bu4NI/tert‐butyl hydroperoxide (TBHP) catalyzed synthesis of amides through a cross‐coupling reaction between acyl and aminyl radicals is described. This method involves the combination of aldehyde CH bond functionalization and decarbonylation of N,N‐disubstituted formamides (see scheme). The cross‐coupling is metal‐free, has a wide substrate scope, operational simplicity, and
自由基溶液:描述了Bu 4 NI /叔丁基过氧化氢(TBHP)通过酰基和氨基自由基之间的交叉偶联反应催化的酰胺合成。该方法涉及醛CH键官能化和N,N-二取代甲酰胺的脱羰作用的组合(请参见方案)。交叉耦合是无金属的,具有广泛的基片范围,操作简便,并且按比例放大可提供高产量。
Formamide Synthesis through Borinic Acid Catalysed Transamidation under Mild Conditions
作者:Tharwat Mohy El Dine、David Evans、Jacques Rouden、Jérôme Blanchet
DOI:10.1002/chem.201600234
日期:2016.4.18
A highly efficient and mild transamidation of amides with amines co‐catalysed by borinic acid and acetic acid has been reported. A wide range of functionalised formamides was synthesized in excellent yields, including important chiral α‐amino acid derivatives, with minor racemisation being observed. Experiments suggested that the reaction rely on a cooperative catalysis involving an enhanced boron‐derived
Prolinamides of formula (1)
wherein R is hydrogen, R₁ is a straight or branched C₂-C₅ alkyl group, ω-substituted with a hydroxyl or carboxyl group optionally esterified with a C₂-C₅ alkanol, or an amino group substituted with one or two straight or branched C₂-C₅ alkyl groups or an amino acid residue, or a 5- or 6- membered heterocyclic group wherein the heteroatom is sulphur or nitrogen, or R and R₁ taken together form a rin of formula
wherein R₃ is a phenyl group optionally substituted with halogens or halogen-substituted lower C₁-C₄ alkyl groups, and R₂ is hydrogen, benzyloxycarbonyl or formyl, are potent enhancers of learning and memory processes.
A Remarkably Simple Protocol for the <i>N</i>-Formylation of Amino Acid Esters and Primary Amines
作者:Mojmír Suchý、Adam A. H. Elmehriki、Robert H. E. Hudson
DOI:10.1021/ol201475j
日期:2011.8.5
A simple, convenient, and wide scope protocol for the N-formylation of amino acid esters and primary amines has been developed utilizing only imidazole in warm DMF.
Concurrent esterification and N-acetylation of amino acids with orthoesters: a useful reaction with interesting mechanistic implications
作者:Sarah Gibson、Dickie Romero、Hollie K. Jacobs、Aravamudan S. Gopalan
DOI:10.1016/j.tetlet.2010.10.081
日期:2010.12
The concurrent esterification and N-acetylation of amino acids has been studied with triethyl orthoacetate (TEOA) and triethyl orthoformate (TEOF). In a surprising finding, only 1 equiv of TEOA in refluxing toluene was necessary to convert L-proline and L-phenylalanine into the corresponding N-acetyl ethyl esters in good yield. The same transformation using TEOF was not effective. Stereochemical outcome and stoichiometric studies as well as structural variation of the amino acids in this reaction provided unexpected mechanistic insight. (C) 2010 Elsevier Ltd. All rights reserved.