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Diversity‐Oriented Synthesis of [2.2]Paracyclophane‐derived Fused Imidazo[1,2‐ a ]heterocycles by Groebke‐Blackburn‐Bienaymé Reaction: Accessing Cyclophanyl Imidazole Ligands Library
Author(s) -
Stahlberger Mareen,
Schwarz Noah,
Zippel Christoph,
Hohmann Jens,
Nieger Martin,
Hassan Zahid,
Bräse Stefan
Publication year - 2022
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202103511
Subject(s) - imidazole , diversity (politics) , chemistry , combinatorial chemistry , stereochemistry , sociology , anthropology
This report describes the synthesis of a [2.2]paracyclophane‐derived annulated 3‐amino‐imidazole ligand library through a Groebke‐Blackburn‐Bienaymé three‐component reaction (GBB‐3CR) approach employing formyl‐cyclophanes in combination with diverse aliphatic and aromatic isocyanides and heteroaromatic amidines. The GBB‐3CR process gives access to skeletally‐diverse cyclophanyl imidazole ligands, namely 3‐amino‐imidazo[1,2‐ a ]pyridines and imidazo[1,2‐ a ]pyrazines. Additionally, a one‐pot protocol for the GBB‐3CR by an in situ generation of cyclophanyl isocyanide is demonstrated. The products were analyzed by detailed spectroscopic techniques, and the cyclophanyl imidazo[1,2‐ a ]pyridine was confirmed unambiguously by single‐crystal X‐Ray crystallography. The cyclophanyl imidazole ligands can be readily transformed to showcase their useful utility in preparing N,C‐palladacycles through regioselective ortho ‐palladation.