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Synthesis and Reduction of Sterically Encumbered Mesoionic Carbene‐Stabilized Aryldihaloboranes
Author(s) -
Arrowsmith Merle,
Böhnke Julian,
Braunschweig Holger,
Gao Haopeng,
Légaré MarcAndré,
Paprocki Valerie,
Seufert Jens
Publication year - 2017
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.201700500
Subject(s) - mesoionic , steric effects , chemistry , carbene , diborane , borane , intramolecular force , ligand (biochemistry) , medicinal chemistry , adduct , isopropyl , geminal , stereochemistry , photochemistry , organic chemistry , catalysis , boron , biochemistry , receptor
Sterically hindered, in situ generated 1,3,4‐substituted 1,2,3‐triazol‐5‐ylidene mesoionic carbenes (MICs) were employed to stabilize a number of aryl‐ and heteroaryldihaloboranes, as well as the first MIC‐supported diborane. Reduction of borane adducts of the 1‐(2,6‐diisopropylphenyl)‐3‐methyl‐4‐ tert ‐butyl‐1,2,3‐triazol‐5‐ylidene ligand with KC 8 in non‐coordinating solvents led to intramolecular C−H‐ and, C−C‐activation at an isopropyl residue of the supporting ligand. DFT calculations showed that each of these activation reactions proceeds via a different isomer of a borylene intermediate.