X-PHOS: Properties and Applications as Catalyst

Description

X-PHOS is a phosphine ligand derived from biphenyl. Its palladium complexes exhibit high activity for Buchwald-Hartwig amination reactions involving aryl chlorides and aryl tosylates.

Properties

X-PHOS is characterized by its remarkable stability and reactivity, emerges as a crucial ligand in catalytic applications, particularly in palladium-catalyzed borylation reactions.

Applications as Catalyst

as a Ligand used in a Pd-catalyzed Suzuki coupling leading to C-15 analogs of vindoline.¹

Direct annulation of 2-haloanilines to indoles and tryptophans catalyzed by Pd. Synthesis of regioregular polythiophenes.

Preferred ligand for greener Sonogashira coupling in TPGS-750-M.

Application of X-PHOS in Palladium-Catalyzed Borylation Reactions

X-PHOS, a phosphine ligand, has shown significant promise in enhancing the efficiency of palladium-catalyzed Miyaura borylation reactions, a critical method for producing aryl boronic acids and esters, essential intermediates in the synthesis of active pharmaceutical ingredients (APIs). This paper demonstrates how using X-PHOS in such reactions enables significant improvements under milder conditions and with lower catalyst loadings. Typically, palladium catalysts require precise ligand control to achieve high activity and selectivity; X-PHOS offers this by providing a robust framework that stabilizes the palladium center, thus facilitating the activation of aryl halides. The advantage of using X-PHOS in the borylation process is evident in the ability to operate at lower temperatures (around 35°C) and complete reactions in less than two hours with a minimal palladium loading of 0.5 mol%. These improvements are not only cost-effective but also reduce the environmental impact associated with metal catalysts. ^{2, 3}

References:

You may like