Convenient synthesis of α-amino amides using low-valent tantalum prepared from TaCl5 and Zn
作者:Haruka Shimizu、Shū Kobayashi
DOI:10.1016/j.tetlet.2005.08.131
日期:2005.10
preparation method of α-amino amides from imines and isocyanates using low-valent tantalum prepared from TaCl5 and Zn in situ. This method was successfully applied to various imines derived from benzaldehyde derivatives with electron-withdrawing or electron-donating substituents, heteroaromatic aldehydes, and an aliphatic, α-branched aldehyde, giving the corresponding α-amino amides in high yields.
Molybdenum-Catalyzed Dehydrogenative Synthesis of Imines from Alcohols and Amines
作者:Kobra Azizi、Robert Madsen
DOI:10.1002/cctc.201800677
日期:2018.9.7
synthesis of imines from primary alcohols and amines with the liberation of dihydrogen. The catalyst is generated in situ from molybdenum hexacarbonyl, 1,3‐dicyclohexylimidazolium chloride and potassium tert‐butoxide and is further stabilized by the phosphine ligand dppe. Imines are formed in moderate to good isolated yields and a variety of alcohols and amines can be employed in the reaction including anilines
Development and mechanistic investigation of the manganese(<scp>iii</scp>) salen-catalyzed dehydrogenation of alcohols
作者:Simone V. Samuelsen、Carola Santilli、Mårten S. G. Ahlquist、Robert Madsen
DOI:10.1039/c8sc03969k
日期:——
The firstexample of a manganese(III) catalyst for the acceptorless dehydrogenation of alcohols is presented. N,N′-Bis(salicylidene)-1,2-cyclohexanediaminomanganese(III) chloride (2) has been shown to catalyze the directsynthesis of imines from a variety of alcohols and amines with the liberation of hydrogen gas. The mechanism has been investigated experimentally with labelled substrates and theoretically
介绍了用于醇的无受体脱氢的锰 ( III ) 催化剂的第一个例子。N , N' -双(水杨基)-1,2-环己烷二氨基锰 ( III ) 氯化物 ( 2 ) 已被证明可催化从各种醇和胺直接合成亚胺,并释放氢气。该机制已经用标记的底物进行了实验研究,并在理论上用 DFT 计算进行了研究。结果表明金属-配体双功能途径,其中salen配体中的两个亚胺基团首先被还原形成锰(III) 酰胺络合物作为催化活性物质。然后通过逐步的外球氢转移发生醇的脱氢,产生氢化锰( III ),从中释放氢气。
In Situ Generated Cobalt Catalyst for the Dehydrogenative Coupling of Alcohols and Amines into Imines
作者:Fabrizio Bottaro、Robert Madsen
DOI:10.1002/cctc.201900392
日期:2019.6.6
An in situ formed cobalt catalyst is developed from cobalt(II)bromide, bis[2‐(diisopropylphosphino)‐4‐methylphenyl]amine and zinc metal. The catalyst mediates the acceptorless dehydrogenative coupling of alcohols and amines into imines with the release of hydrogen gas and the transformation is applied to the synthesis of a variety of imines from different alcohols and amines. The mechanism is investigated
One-pot synthesis of optically active 1,4-disubstituted-3-carbamoyl-azetidinones from 5-[(N-arylamino)(hydroxyl)methylene]-2,2-dimethyl-1,3-dioxa-4,6-diones and chiral aldimines is achieved via thermal generation of carbamoyl ketenes and subsequent [2+2] cycloaddition. Three possible chiral induction approaches were tested and (R)-(+)-1-phenylethylamine was confirmed as the best chiral auxiliary. Among