Ammonia-borane as a Catalyst for the Direct Amidation of Carboxylic Acids
作者:P. Veeraraghavan Ramachandran、Henry J. Hamann
DOI:10.1021/acs.orglett.1c00591
日期:2021.4.16
Ammonia-borane serves as an efficient substoichiometric (10%) precatalyst for the direct amidation of both aromatic and aliphatic carboxylicacids. In situ generation of amine-boranes precedes the amidation and, unlike the amidation with stoichiometric amine-boranes, this process is facile with 1 equiv of the acid. This methodology has high functional group tolerance and chromatography-free purification
Copper-catalyzed one-pot oxidative amidation of both aliphatic and aromatic alcohols with N-chloramines, prepared in situ from many types of primary and secondary amines, to form amides under mild conditions.
General and Efficient α-Oxygenation of Carbonyl Compounds by TEMPO Induced by Single-Electron-Transfer Oxidation of Their Enolates
作者:Emanuela Dinca、Philip Hartmann、Jakub Smrček、Ina Dix、Peter G. Jones、Ullrich Jahn
DOI:10.1002/ejoc.201200736
日期:2012.8
for the synthesis of protected α-oxygenated carbonylcompounds is reported. It is based on the single-electron-transfer oxidation of easily generated enolates to the corresponding α-carbonyl radicals. Coupling with the stable free radical TEMPO provides α-(piperidinyloxy) ketones, esters, amides, acids or nitriles in moderate-to-excellent yields. Enolate aggregates influence the outcome of the oxygenation
Versatile and chemoselective C–C bond forming methods for the one-pot transformation of amides into other classes of compounds are highly demanding. In this report, we demonstrate the reductive addition of isocyanoacetates to common amides and lactams to produce 5-methoxyoxazoles or bicyclic imidazolines. This one-potprocedure involves partial reduction of amides with Schwartz reagent and chemoselective
The chiral samarium(II) complex prepared from SmI2, (R)-BINOL, and an achiral tertiary amine promoted the reductive homo-coupling reaction of β-monosubstituted acrylic acidamides to give the corresponding 3,4-trans-disubstituted adipamides with high enantioselectivities (up to 85% ee).