Yttrium (amidate) complexes for catalytic C–N bond formation. Rapid, room temperature amidation of aldehydes

Abstract

Yttrium (amidate) precatalysts are highly active for the mild amidation of aldehydes with amines. Reactions occur at room temperature within 5 min in up to 98% isolated yield. These rare-earth systems are effective for this transformation in the absence of supplementary heat, light, base, or oxidants. The reaction proceeds with functionalized amines and/or aldehydes. A comparison of various amidate precatalysts in combination with reaction monitoring suggests that the targeted amide products formed during the reaction promote the formation of alternative catalytically active amidate species in situ.

Gold(I)‐katalysierte diastereoselektive Hydroacylierung terminaler Alkine mit Glyoxalen

“…Daher wurden alle Katalysatoren bei dieser erhçhten Temperatur getestet. Unter den verwendeten Gold(III)-Salzen erwies sich Dichloro(2-pyridincarboxylato)gold [6] ( [7] Als nächstes wurde die Anwendungsbreite dieser Kaskadenreaktion mit verschiedenen Glyoxalen 1 und terminalen Alkinen 2 unter den optimierten Bedingungen erprobt (2.0 ¾quiv. Piperidin, 10 Mol-% AuCl, Toluol, N 2 -Atmosphäre, 50 8C).…”

Direct synthesis of amides from nonactivated carboxylic acids using urea as nitrogen source and Mg(NO3)2or imidazole as catalysts

“…14, and 15), with internal (16) and terminal (17) double bonds were also well-tolerated. Aliphatic acids containing conjugated double bonds (18) were more challenging substrates and lower conversions were observed even at elevated temperatures. The precursor benzoic acid (10) and substituted acids 11 and 12 showed very low reactivity under the reaction conditions, perhaps due to the delocalisation of electrons and subsequent decrease of electrophilicity of the carboxyl group.…”

“…Besides, the removal of the corresponding by-product can be tedious increasing the cost of the transformation. New methodologies described for the synthesis of amides 5,6 involve the use of catalysts, and employ starting materials such as esters, [7][8][9][10][11][12][13][14][15][16][17] aldehydes, [18][19][20][21][22][23][24][25][26][27] alcohols, [28][29][30][31][32][33] nitriles, [34][35][36][37][38][39][40][41][42][43][44][45] and oximes. [46][47][48][49][50][51][52][53][54]…”

“…Besides, the removal of the corresponding by-product can be tedious increasing the cost of the transformation. New methodologies described for the synthesis of amides 5 , 6 involve the use of catalysts, and employ starting materials such as esters, 7 – 17 aldehydes, 18 – 27 alcohols, 28 – 33 nitriles, 34 – 45 and oximes. 46 – 56 The catalysts are mainly based on expensive metals such as rhodium, ruthenium, iridium, and palladium.…”

Gold(I)‐Catalyzed Diastereoselective Hydroacylation of Terminal Alkynes with Glyoxals

“…Furthermore, oxygen must be excluded from the reaction system as otherwise a-ketoamides will be produced in quantitative yields (Scheme 2). [7] Next we explored the scope of this cascade reaction by using glyoxals 1 and terminal alkynes 2 under the optimized . conditions (2.0 equiv of piperidine, 10 mol % AuCl, toluene, N 2 atmosphere, 50 8C).…”