ligand-free MnO2 mediated sequentialoxidation and olefination has been developed for the facile synthesis of a broad range of unsaturated N-heteroazaarenes from simple alkyl-substituted heteroarenes and alcohols. The procedure tolerates a series of functional groups, such as methoxyl, chloro, bromo, iodo, vinyl, phenolic and hetero groups, providing the olefination products in moderate to good yields
An efficient nickel-catalyzed acceptorless dehydrogenative coupling of methyl-substituted heteroarenes with primary alcohols is achieved using an in situ generated complex of inexpensive NiBr2 and readilyavailable 8-aminoquinoline picolinic amide ligand. The protocol is operationally simple and scalable and furnishes a series of high-value 2-alkenylheteroarenes in good yields (up to 88%) with exclusive
aldehydes has been achieved through a novel synergistic organocatalysis. The HOAc‐ activated 2‐methylquiolines undergo a Michael addition to 1,3‐dimethylbarbituricacid‐activated aldehydes, followed by a retro‐Michael addition to release 1,3‐dimethylbarbituricacid and the target products. The transformation produced various 2‐alkenylquinolines with good to excellent yields and featured mild reaction conditions
NaCl as Catalyst and Water as Solvent: Highly <i>E</i>-Selective Olefination of Methyl Substituted <i>N</i>-Heteroarenes with Benzyl Amines and Alcohols
作者:Susanta Hazra、Vikas Tiwari、Ashutosh Verma、Pritam Dolui、Anil J. Elias
DOI:10.1021/acs.orglett.0c01851
日期:2020.7.17
Oxidative coupling of benzylamines and alcohols with methyl substituted N-heteroarenes such as quinolines and quinoxalines has been achieved using chloride, a sea abundant anion as the catalyst for practical synthesis of a wide range of E-disubstituted olefins in aqueous medium. Detailed mechanistic studies and control experiments were carried out to deduce the reaction mechanism which indicated that