Highly stereoselective synthesis of novel spiroimidazolidinones directed by pyridine prolinamide
摘要:
A facile approach to the stereoselective synthesis of spiroimidazolidinones was described. A variety of novel polycyclic spiroimidazolidinones derived from isatin were prepared by employing easily available 2-pyridyl prolinamide as a chiral scaffold. Interestingly, the N-2-pyridyl motif played a vital role in improving the diastereoselectivity of this protocol. As a result, excellent diastereoselectivities (>20:1 dr) and good to excellent yields (60-96%) were achieved under extremely mild reaction conditions. (C) 2014 Elsevier Ltd. All rights reserved.
An ionic 2,6-bis(imidazo[1,2-α]pyridin-2-yl)pyridine-based N^N^N pincer ruthenium(II) complex exhibited high efficiency in the C–N bond formation between amines and alcohols by the “borrowing hydrogen” (BH) or “hydrogen autotransfer” (HA) concept. The synthetic protocol selectively generated monoalkylated amines without formation of tertiary amines during the reaction. The unique selectivity enabled
Selective Iridium-Catalyzed Alkylation of (Hetero)Aromatic Amines and Diamines with Alcohols under Mild Reaction Conditions
作者:Benoît Blank、Stefan Michlik、Rhett Kempe
DOI:10.1002/chem.200802318
日期:2009.4.6
Selective amine alkylation: A P,N‐ligand‐stabilized iridium complex has been used as an efficientcatalyst for the alkylation of (hetero)aromatic amines with alcohols at mild reaction temperatures and catalyst loadings as low as 0.1 mol % Ir (see scheme). The excellent selectivity of the catalyst for monoalkylation of the amine function has also been exploited for the N,N′‐dialkylation of diamines
Control over borrowing hydrogen and acceptorless dehydrogenative coupling process for the Co(<scp>iii</scp>)–NHC catalysed chemoselective alkylation and cyclisation of 1,2-phenylenediamine with alcohols
作者:Misba Siddique、Biswaranjan Boity、Arnab Rit
DOI:10.1039/d3cy01235b
日期:——
alcohol exploiting a single catalyst system has remained unexplored. Herein, we report the chemoselective effective alkylation and cyclisation of 1,2-phenylenediamine with alcohol by simply switching the substituent on the supporting NHC ligand of cobalt(III) complexes. This varying catalytic behaviour of the complexes under consideration towards the selective formation of different products was fairly understood
利用单一催化剂体系使用醇对 1,2-苯二胺进行烷基化或环化的一锅法尚未得到探索。在此,我们报道了通过简单地切换钴( III )配合物的支撑NHC配体上的取代基,1,2-苯二胺与醇的化学选择性有效烷基化和环化。通过基于 NMR、电化学和 DFT 研究分析复合物的电子特性,可以很好地理解复合物选择性形成不同产物的不同催化行为。此外,本协议与各种结构多样的底物兼容,提供丰富的胺和醇变化,从 1,2-苯二胺开始生产四种不同类型的产品。最后,一系列对照实验,包括氘标记和不同中间体的鉴定,有助于建立所提出的机制。
Czuba, Wladyslaw; Kowalski, Piotr, Polish Journal of Chemistry, 1980, vol. 54, # 4, p. 853 - 855
作者:Czuba, Wladyslaw、Kowalski, Piotr
DOI:——
日期:——
Self-Complementarity of Oligo-2-aminopyridines: A New Class of Hydrogen-Bonded Ladders
A new class of hydrogen-bonded ladders based on hydrogen-bonded dimerization of oligo-alpha-aminopryidines has been demonstrated. Jorgensen's model can be successfully applied to this hydrogen-bonding system in nonpolar solvents. The results show the competitive enthalpy/entropy compensation relationship upon dimerization, Although increasing the number of hydrogen-bonding interactions would enhance the hydrogen-bonding stabilization enthalpy, this stabilization enthalpy per unit would be partially sacrificed to compensate for the entropy loss due to dimerization. These results clearly support the importance of preorganization in designing hydrogen-bonding guest-host molecules.