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Catalyst‐Controlled Regiodivergent CH Borylation of Multifunctionalized Heteroarenes by Using Iridium Complexes
Author(s) -
Sasaki Ikuo,
Taguchi Jumpei,
Hiraki Shotaro,
Ito Hajime,
Ishiyama Tatsuo
Publication year - 2015
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.201500658
Subject(s) - borylation , regioselectivity , iridium , chemistry , catalysis , medicinal chemistry , combinatorial chemistry , organic chemistry , alkyl , aryl
The regiodivergent CH borylation of 2,5‐disubstituted heteroarenes with bis(pinacolato)diboron was achieved by using iridium catalysts formed in situ from [Ir(OMe)(cod)] 2 /dtbpy (cod=1,5‐cyclooctadiene, dtbpy: 4,4′‐di‐ tert ‐butyl‐2,2′‐bipyridine) or [Ir(OMe)(cod)] 2 /2 AsPh 3 . When [Ir(OMe)(cod)] 2 /dtbpy was used as the catalyst, borylation at the 4‐position proceeded selectively to afford 4‐borylated products in high yields (dtbpy system A). The regioselectivity changed when the [Ir(OMe)(cod)] 2 /2 AsPh 3 catalyst was used; 3‐borylated products were obtained in high yields with high regioselectivity (AsPh 3 system B). The regioselectivity of borylation was easily controlled by changing the ligands. This reaction was used in the syntheses of two different bioactive compound analogues by using the same starting material.