93801-39-9Relevant academic research and scientific papers
Catalysis through temporary intramolecularity: Mechanistic investigations on aldehyde-catalyzed cope-type hydroamination lead to the discovery of a more efficient tethering catalyst
Guimond, Nicolas,MacDonald, Melissa J.,Lemieux, Valerie,Beauchemin, Andre M.
, p. 16571 - 16577,7 (2020/09/15)
Mechanistic investigations on the aldehyde-catalyzed intermolecular hydroamination of allylic amines using N-alkylhydroxylamines are presented. Under the reaction conditions, the presence of a specific aldehyde catalyst allows formation of a mixed aminal intermediate, which permits intramolecular Cope-type hydroamination. The reaction was determined to be first-order in both the aldehyde catalyst (α-benzyloxyacetaldehyde) and the allylic amine. However, the reaction displays an inverse order behavior in benzylhydroxylamine, which reveals a significant off-cycle pathway and highlights the importance of an aldehyde catalyst that promotes a reversible aminal formation. Kinetic isotope effect experiments suggest that hydroamination is the rate-limiting step of this catalytic cycle. Overall, these results enabled the elaboration of a more accurate catalytic cycle and led to the development of a more efficient catalytic system for alkene hydroamination. The use of 5-10 mol % of paraformaldehyde proved more effective than the use of 20 mol % of α-benzyloxyacetaldehyde, leading to high yields of intermolecular hydroamination products within 24 h at 30 °C.
Synthesis of aryloxyacetaldehydes and N-(aryloxyethyl)cyclohexanamine hydrochloroides
Shapenova,Belyatskii,Panicheva
experimental part, p. 1017 - 1020 (2010/10/21)
Oxidation of 2-(aryloxymethyl)oxiranes with periodic acid gave a series of aryloxyacetaldehydes which reacted with cyclohexylamine in THF, and subsequent reduction of Schiff bases thus obtained with sodium tetrahydridoborate resulted in the formation of the corresponding secondary amines which were isolated and characterized as hydrochlorides.
N-heterocyclic carbene-catalyzed enantioselective mannich reactions with α-aryloxyacetaldehydes
Kawanaka, Yasufumi,Phillips, Eric M.,Scheidt, Karl A.
supporting information; experimental part, p. 18028 - 18029 (2010/03/26)
(Chemical Equation Presented) N-Heterocyclic carbenes (NHCs) catalyze a new Mannich-type reaction to form β-amino acid derivatives in high yield and enantioselectivity. The reaction is initiated by the addition of an NHC to an C-aryloxyaldehyde followed by elimination of a phenoxide anion which generates an enol/enolate. A Mannich addition to a tosylimine proceeds with excellent control over enantioselectivity. In a new carbene catalysis concept, catalyst regeneration is promoted by return, or rebound, and acylation of the phenoxide group which served as the activating component in the first step of the catalytic cycle. The activated ester products formed in situ are manipulated to form a variety of useful compounds including β-amino acids, β-amino amides, and peptides.
Ozonolysis of Olefins VIII [1]. Synthesis of Phenoxyacetaldehydes by Ozonolysis of Allylphenylethers
Jellen,Mittelbach,Junek
, p. 167 - 172 (2007/10/03)
A new route for the preparation of a series of phenoxyacetaldehydes (2a-j) which are useful intermediates or products, is described. It starts from the easily available allylphenylethers 1a-j which are ozonized at -40°C and further treated with dimethylsulfide to give solutions of the corresponding phenoxyacetaldehydes 2a-j; these are purified by column chromatography. Reaction of 2a-j with 1-methyl-1-phenylhydrazine leads to the corresponding hydrazones 3a-c, 3e-g, 3i, and 3j. The aldehydes can also be transformed into the stable dimethylcetals 4a, 4e, 4h, and 4i by reaction with trimethyl orthoformate.
New non-proteogenic aminoacids bearing an enol aryl-ether moiety
Daumas,Vo-Quang,Le Goffic
, p. 2373 - 2384 (2007/10/02)
Aminoacids bearing an enol aryl-ether moiety have been synthesized by a new method allowing a great versatility in the introduction of N-protective groups and enol ether functions. This method involves a Wittig-Horner condensation affording alpha, beta-dehydrohomoserine ether derivatives, followed by a regio and stereoselective isomerization into the desired E enol ether. Clean deprotection was achieved providing new 2-amino-4-aryloxybut-3(E)-enoic acids 3.
