11 research outputs found
Scope of the Two-Step, One-Pot Palladium-Catalyzed Borylation/Suzuki Cross-Coupling Reaction Utilizing Bis-Boronic Acid
The use of bis-boronic acid for the direct synthesis
of boronic acids has greatly facilitated the two-step, one-pot borylation/Suzuki
cross-coupling reaction between aryl and heteroaryl halides. With
use of Buchwald’s second-generation XPhos preformed catalyst,
high yields of cross-coupled products were obtained for most substrates.
The method also allows an efficient two-step, one-pot synthesis, providing
access to three distinct cross-coupled products after column chromatography.
The method also provides a rapid and convenient route to teraryl compounds
Palladium-Catalyzed Borylation of Aryl and Heteroaryl Halides Utilizing Tetrakis(dimethylamino)diboron: One Step Greener
The palladium-catalyzed borylation of aryl and heteroaryl halides with a novel borylating agent, tetrakis(dimethylamino)diboron [(Me<sub>2</sub>N)<sub>2</sub>B–B(NMe<sub>2</sub>)<sub>2</sub>], is reported. The method is complementary to the previously reported method utilizing bis-boronic acid (BBA) in that certain substrates perform better under one set of optimized reaction conditions than the other. Because tetrakis(dimethylamino)diboron is the synthetic precursor to both BBA and bis(pinacolato)diboron (B<sub>2</sub>Pin<sub>2</sub>), the new method represents a more atom-economical and efficient approach to current borylation methods
Scope of the Palladium-Catalyzed Aryl Borylation Utilizing Bis-Boronic Acid
The Suzuki-Miyaura reaction has become one of the more
useful tools
for synthetic organic chemists. Until recently, there did not exist
a direct way to make the most important component in the coupling
reaction, namely the boronic acid. Current methods to make boronic
acids often employ harsh or wasteful reagents to prepare boronic acid
derivatives and require additional steps to afford the desired boronic
acid. The scope of the previously reported palladium-catalyzed, direct
boronic acid synthesis is unveiled, which includes a wide array of
synthetically useful aryl electrophiles. It makes use of the newly
available second generation Buchwald XPhos preformed palladium catalyst
and bis-boronic acid. For ease of isolation and to preserve the often
sensitive C–B bond, all boronic acids were readily converted
to their more stable trifluoroborate counterparts