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New Manganese‐Terpyridine‐Based Catalytic System for the Dehydrogenative Coupling of Alcohols and Amines for the Synthesis of Aldimines
Author(s) -
Lim Hyun,
Chohan Prianka,
Moustafa Dina,
Sweet Chelsea,
Calalpa Brenda,
Kaur Parminder
Publication year - 2018
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201801325
Subject(s) - aldimine , manganese , terpyridine , catalysis , chemistry , yield (engineering) , combinatorial chemistry , coupling reaction , substrate (aquarium) , polymer chemistry , organic chemistry , metal , materials science , oceanography , metallurgy , geology
We have developed novel Manganese‐terpyridine ( Terpy ) and Terpy‐derivative systems for dehydrogenative coupling of amines and alcohols in the presence of air. A variety of manganese salts were first screened and the effects of temperature, extent of catalytic loading, and different terpyridine derivatives on the efficiency of the reaction were thoroughly studied. The resulting aldimines were isolated in moderate to high yields, exhibiting the broad substrate scope of the reaction. The high yields of aldimines were obtained in the presence of both electron‐donating and electron‐withdrawing groups on alcohols and amines. However, with 4‐aminophenol and 2‐aminophenol, a steep decrease in the product yield was observed. The new system exhibits numerous advantages, such as the use of an inexpensive non‐precious metal like manganese, operational simplicity and simpler ligands. To the best of our knowledge, this is the first report where Mn‐Terpy catalytic system has been used for the synthesis of aldimines, well‐known substrates for a variety of addition reactions, through the dehydrogenative coupling reaction of alcohols with amines. The Mn‐Terpy complex is anticipated to form a dinuclear complex that controls the oxidation state of manganese to carry out the necessary dehydrogenative coupling.