Open AccessSelective ortho-C–H Activation in Arenes without Functional Groups
Author(s) -
Antony P. Y. Chan,
Martin Jakoobi,
Chenxu Wang,
Robert T. O’Neill,
Gülsevim S S Aydin,
Nathan R. Halcovitch,
Roman Boulatov,
Alexey G. Sergeev
Publication year - 2022
Publication title -
journal of the american chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.115
H-Index - 612
eISSN - 1520-5126
pISSN - 0002-7863
DOI - 10.1021/jacs.2c04621
Subject(s) - chemistry , iridium , substituent , alkyl , reductive elimination , medicinal chemistry , yield (engineering) , molecule , selectivity , stereochemistry , organic chemistry , catalysis , materials science , metallurgy
Aromatic C-H activation in alkylarenes is a key step for the synthesis of functionalized organic molecules from simple hydrocarbon precursors. Known examples of such C-H activations often yield mixtures of products resulting from activation of the least hindered C-H bonds. Here we report highly selective ortho -C-H activation in alkylarenes by simple iridium complexes. We demonstrate that the capacity of the alkyl substituent to override the typical preference of metal-mediated C-H activation for the least hindered aromatic C-H bonds results from transient insertion of iridium into the benzylic C-H bond. This enables fast iridium insertion into the ortho -C-H bond, followed by regeneration of the benzylic C-H bond by reductive elimination. Bulkier alkyl substituents increase the ortho selectivity. The described chemistry represents a conceptually new alternative to existing approaches for aromatic C-H bond activation.