Selective catalytic Hofmann N-alkylation of poor nucleophilic amines and amides with catalytic amounts of alkyl halides
作者:Qing Xu、Huamei Xie、Er-Lei Zhang、Xiantao Ma、Jianhui Chen、Xiao-Chun Yu、Huan Li
DOI:10.1039/c6gc00938g
日期:——
A selective Hofmann N-alkylation reaction of amines/amides catalytic in alkylhalides is achieved by using alcohols as the alkylating reagents, affording mono- or di-alkylated amines/amides in high selectivities.
Efficient and practical catalyst-free-like dehydrative N-alkylation of amines and sulfinamides with alcohols initiated by aerobic oxidation of alcohols under air
We developed simple and practical N-alkylation reactions of amines and sulfinamides with primary and secondary alcohols by using only catalytic amounts of air as the initiator without adding any external catalysts. This method has advantages of simple conditions, easy operation, and comparatively wider scope of substrates, providing an efficient and green catalyst-free-like alcohol-based dehydrative N-alkylation method. Mechanistic studies revealed that air initiated the reactions by aerobic oxidation of the alcohols to the key initiating aldehydes or ketones in the presence of bases. (C) 2015 Elsevier Ltd. All rights reserved.
A Mild, One-Pot Synthesis of Arylamines<i>via</i>Palladium- Catalyzed Addition of Aryl Aldehydes with Amines and Arylboronic Acids in Water
作者:Ajuan Yu、Yangjie Wu、Baoli Cheng、Kun Wei、Jingya Li
DOI:10.1002/adsc.200800680
日期:2009.3
Abstractmagnified imageA mild, one‐pot synthesis of diarylmethylamines via the palladium‐catalyzed addition of aryl aldehydes with amines and arylboronic acids is reported. Best results were obtained in neat water with ammonium chloride as additive, affording diarylmethylamine derivatives as the main products.
EPR and ENDOR study of chiral nitroxides
作者:Hartmut B. Stegmann、Frank‐Martin Schaber、Paul Schuler、Klaus Scheffler
DOI:10.1002/mrc.1260270912
日期:1989.9
Racemic and achiral alkyl aryl nitroxides were examined at various temperatures. The restricted rotation of the aminoxyl substituents was indicated both by the β-proton coupling constants and by the inequivalence of the aromatic ortho protons. These results are interpreted by the presence of two different rotamers which may lead to two splitting constants for the β-proton. The capability for inter- and intra-molecular hydrogen bond formation in the nitroxides investigated was demonstrated. However, complexes consisting of chiral radicals and chiral auxiliaries do not show hyperfine structures which unambiguously indicate diastereomeric species. Therefore, hydrogen bonding between chiral molecules is not sufficient for chiral recognition if an alteration of the hyperconjugation angle does not occur. Simple steric interactions can result in the doubling of the β-proton coupling constant, independently of diastereomeric complex formation.