Aminoborylation/Suzuki–Miyaura tandem cross coupling of aryl iodides as efficient and selective synthesis of unsymmetrical biaryls

Abstract

Sequential borylation of a first aryl iodide using a dialkylaminoborane followed by a Suzuki-Miyaura cross coupling of second aryl iodide ended up with an efficient, selective and practical synthesis of unsymmetrical biaryls. This tandem coupling shows a wide range of applicability.

Novel biphenyl ester derivatives as tyrosinase inhibitors: Synthesis, crystallographic, spectral analysis and molecular docking studies

“…The aromatic carbon signals of biphenyl and benzene groups were found in the range of δ ≈152 to 110 ppm. The –CH 3 and –OCH 3 carbon signals of compounds 2 ( f - k ) were located in the up-field region centering at δ ≈21 and 56 ppm, respectively [ 28 , 29 ].…”

Iron‐Catalysed Borylation of Arenediazonium Salts to Give Access to Arylboron Derivatives via Aryl(amino)boranes at Room Temperature

“…Aminoboranes11 such as ( i‐ Pr) 2 N‐BH 2 1d have been used since 2003 as borylation agent in palladium‐catalysed transformations of aryl bromides, iodides and triflates 12. We recently extended the use of such aminoboranes for the direct synthesis of biaryl compounds,13 which was part of our ongoing research project on designing a better access to and use of boron derivatives. Herein, we describe an iron‐catalysed borylation of arenediazonium salts which proceeds at room temperature with high catalytic activities.…”

Borylation of Unactivated Aryl Chlorides under Mild Conditions by Using Diisopropylaminoborane as a Borylating Reagent

“…Since 2003, aminoboranes have been used as borylation agents in palladium‐catalyzed transformations of aryl bromides, iodides, and triflates (Scheme ) 11. We recently extended the use of such aminoboranes for the direct synthesis of biaryl compounds,12 and also employed aminoboranes in iron‐,7c zirconium‐,7d and titanium‐catalyzed7d borylation of arenediazonium salts. In these reactions, BH 2 N i Pr 2 1 , which is readily prepared by the thermally‐induced dehydrogenation of a diisopropylamine–borane complex, was used.…”

“…, entries[10][11][12][13]. Additionally, sterically hindered aryl chlorides bearing multiple substituents (2 o, 2 p, 2 t, and 2 u) afforded the desired ester compounds 4 o, 4 p, 4 t, and 4 u in 76 to 97 % yield…”