Under open-flask conditions in the presence of commercially available FeCl3·6H2O, N,N-disubstituted anilines can be converted into diversely functionalized benzidines with yields of up to 99%. Oxidative coupling was extended to N-monosubstituted anilines, and the method was applied to the efficient preparation of 6,6′-biquinoline. Mechanistic investigations have also been performed to explain the observed
Transition Metal-Free Oxidative Coupling of Primary Amines in Polyethylene Glycol at Room Temperature: Synthesis of Imines, Azobenzenes, Benzothiazoles, and Disulfides
作者:Abhinandan D. Hudwekar、Praveen K. Verma、Jaspreet Kour、Shilpi Balgotra、Sanghapal D. Sawant
DOI:10.1002/ejoc.201801610
日期:2019.2.14
A transition metal‐free protocol has been developed for the oxidativecoupling of primary amines to imines and azobenzenes, thiols to disulfides, and 2‐aminothiophenols to benzothiazoles, offering excellent yields. The advantageous features of the present environmentally benign methodology include the usage of biocompatable and green reaction conditions such as solvent, room temperature reactions,
replacement in catalysis is especially interesting if different catalytic reactivity is observed. We report, here, on the selective manganese-catalyzed base-switchable synthesis of N-alkylated amines or imines. In both reactions, borrowing hydrogen/hydrogen autotransfer (N-alkyl amine formation) or dehydrogenative condensation (imineformation), we start from the same amines and alcohols and use the same
Switchable imine and amine synthesis catalyzed by a tripodal ligand-supported well-defined cobaltcomplex is presented herein. A large variety of primary alcohols and amines were selectively converted to imines or amines in good to excellent yields. It is discovered that the base plays a crucial role on the selectivity. A catalytic amount of base leads to the imine formation, while an excess loading
Central‐to‐Axial Chirality Conversion Approach Designed on Organocatalytic Enantioselective Povarov Cycloadditions: First Access to Configurationally Stable Indole–Quinoline Atropisomers
stereoselective synthesis of enantioenriched axially chiral indole-quinoline systems is presented. The strategy takes advantage of an organocatalytic enantioselective Povarov cycloaddition of 3-alkenylindoles and N-arylimines, followed by an oxidative central-to-axial chirality conversion process, allowing for access to previously unreported axially chiral indole-quinoline biaryls. The methodology