117847-16-2Relevant academic research and scientific papers
Development of an aryl amination catalyst with broad scope guided by consideration of catalyst stability
McCann, Scott D.,Reichert, Elaine C.,Arrechea, Pedro Luis,Buchwald, Stephen L.
supporting information, p. 15027 - 15037 (2020/10/13)
We have developed a new dialkylbiaryl monophosphine ligand, GPhos, that supports a palladium catalyst capable of promoting carbon-nitrogen cross-coupling reactions between a variety of primary amines and aryl halides; in many cases, these reactions can be carried out at room temperature. The reaction development was guided by the idea that the productivity of catalysts employing BrettPhos-like ligands is limited by their lack of stability at room temperature. Specifically, it was hypothesized that primary amine and N-heteroaromatic substrates can displace the phosphine ligand, leading to the formation of catalytically dormant palladium complexes that reactivate only upon heating. This notion was supported by the synthesis and kinetic study of a putative off-cycle Pd complex. Consideration of this off-cycle species, together with the identification of substrate classes that are not effectively coupled at room temperature using previous catalysts, led to the design of a new dialkylbiaryl monophosphine ligand. An Ot-Bu substituent was added ortho to the dialkylphosphino group of the ligand framework to improve the stability of the most active catalyst conformer. To offset the increased size of this substituent, we also removed the para i-Pr group of the non-phosphorus-containing ring, which allowed the catalyst to accommodate binding of even very large α-tertiary primary amine nucleophiles. In comparison to previous catalysts, the GPhos-supported catalyst exhibits better reactivity both under ambient conditions and at elevated temperatures. Its use allows for the coupling of a range of amine nucleophiles, including (1) unhindered, (2) five-membered-ring N-heterocycle-containing, and (3) α-tertiary primary amines, each of which previously required a different catalyst to achieve optimal results.
Aminocyanation by the addition of N-CN bonds to arynes: Chemoselective synthesis of 1,2-bifunctional aminobenzonitriles
Rao, Bin,Zeng, Xiaoming
supporting information, p. 314 - 317 (2014/01/23)
An efficient aminocyanation by the direct addition of aryl cyanamides to arynes is described, enabling incorporation of highly useful amino and cyano groups synchronously via cleavage of inert N-CN bonds, affording synthetically useful 1,2-bifunctional aminobenzonitriles. The postsynthetic functionalization of the aminocyanation products allows diverse formation of synthetically important derivatives such as drug molecule Ponstan and fused heterocycles.
Aromatic Nitro group Displacement Reactions. Part 2. The Synthesis of Diarylamines and some Heteroaromatic Analogues.
Gorvin, John H.
, p. 1662 - 1681 (2007/10/02)
In dipolar aprotic solvents, activated aromatic nitro-groups can usually be displaced by anilines of enhanced N-acidity in the presence of the heavier alkali-metal carbonates.When catalysed by potassium t-butoxide, however, attack occurs preferentially at other reactive centers in the molecule, except where the nitro-group is highly activated.Some of the resulting diarylamines (the term is here expanded to include arylaminoxanthen-9-ones) are intermediates in the synthesis of heterocycles.
The Synthesis of Di- and Tri-arylamines through Halogen Displacement by Base-activated Arylamines: Comparison with the Ullmann Condensation
Gorvin, John H.
, p. 1331 - 1336 (2007/10/02)
In dipolar aprotic solvents, nitranions derived from anilines of enhanced N-acidity displace fluorine from activated aromatic compounds at room temperature.Diarylamines thus produced are free from triarylamines, which are formed at higher temperatures when diarylamines, after N-deprotonation by potassium t-butoxyde or by the heavier alkali metal carbonates, similarly displace activated fluorine.Certain diarylamines can also be prepared by chlorine displacement in the presence of alkali metal carbonates.It is confirmed that such carbonates play only an auxiliary role in the Ullmann (copper-assisted) diarylamine synthesis conducted in dipolar aprotic solvents; they may indeed impede the reaction in some instances.
