TY - JOUR
T1 - Regioselective Iridium-Catalyzed C8-H Borylation of 4-Quinolones via Transient O-Borylated Quinolines
AU - Al Mamari, Hamad H.
AU - Borel, Julie
AU - Hickey, Aobha
AU - Courtney, Eimear
AU - Merz, Julia
AU - Zhang, Xiaolei
AU - Friedrich, Alexandra
AU - Marder, Todd B.
AU - McGlacken, Gerard P.
N1 - Publisher Copyright:
© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.
PY - 2023/7/19
Y1 - 2023/7/19
N2 - The quinolone–quinoline tautomerization is harnessed to effect the regioselective C8-borylation of biologically important 4-quinolones by using [Ir(OMe)(cod)]2 as the catalyst precursor, the silica-supported monodentate phosphine Si-SMAP as the ligand, and B2pin2 as the boron source. Initially, O-borylation of the quinoline tautomer takes place. Critically, the newly formed 4-(pinBO)-quinolines then undergo N-directed selective Ir-catalyzed borylation at C8. Hydrolysis of the OBpin moiety on workup returns the system to the quinolone tautomer. The C8-borylated quinolines were converted to their corresponding potassium trifluoroborate (BF3K) salts and to their C8-chlorinated quinolone derivatives. The two-step C-H borylation-chlorination reaction sequence resulted in various C8-Cl quinolones in good yields. Conversion to C8-OH-, C8-NH2-, and C8-Ar-substituted quinolones was also feasible by using this methodology.
AB - The quinolone–quinoline tautomerization is harnessed to effect the regioselective C8-borylation of biologically important 4-quinolones by using [Ir(OMe)(cod)]2 as the catalyst precursor, the silica-supported monodentate phosphine Si-SMAP as the ligand, and B2pin2 as the boron source. Initially, O-borylation of the quinoline tautomer takes place. Critically, the newly formed 4-(pinBO)-quinolines then undergo N-directed selective Ir-catalyzed borylation at C8. Hydrolysis of the OBpin moiety on workup returns the system to the quinolone tautomer. The C8-borylated quinolines were converted to their corresponding potassium trifluoroborate (BF3K) salts and to their C8-chlorinated quinolone derivatives. The two-step C-H borylation-chlorination reaction sequence resulted in various C8-Cl quinolones in good yields. Conversion to C8-OH-, C8-NH2-, and C8-Ar-substituted quinolones was also feasible by using this methodology.
KW - Bioactive
KW - C−H activation
KW - boronate ester
KW - boronic acid
KW - tautomer
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UR - https://www.mendeley.com/catalogue/50e57025-d4e0-358c-8d5a-4ddebcf23847/
U2 - 10.1002/chem.202301734
DO - 10.1002/chem.202301734
M3 - Article
C2 - 37280155
AN - SCOPUS:85165291326
SN - 0947-6539
VL - 29
SP - e202301734
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
IS - 48
M1 - e202301734
ER -