The palladium-catalyzed cross-coupling reaction between different types of organoboron compounds and various organic electrophiles including halides or triflates in the presence of base provides a powerful and general methodology for the formation of carbon-carbon bonds. The (sp2)C-B compounds (such as aryl- and 1-alkenylboron derivatives) and (sp3)C-B compounds (alkylboron compounds) readily cross-couple with organic electrophiles to give coupled products selectively in high yields. Recently, the (sp)C-B compounds (1-alkynylboron derivatives) have been also observed to react with organic electrophiles to produce expected cross-coupled products.
Such coupling reactions offer several advantages: (1) ready availability of reactants; (2) mild reaction conditions: (3) water stability; (4) easy use of the reaction both in aqueous and heterogeneous conditions; (5) toleration of a broad range of functional groups; (6) high regio- and stereoselectivity of the reaction; (7) insignificant effect of steric hindrance; (8) use of a small amount of catalysts; (9) application in one-pot synthesis; (10) nontoxic reaction; and (11) easy separation of inorganic boron compound.
These coupling reactions have been actively utilized not only in academic fields but also in industrial processes.
In this lecture, the overview of the coupling reaction will be discussed to understand the outlines.