page_title: Dialkylbiaryl phosphine ligands
section_title: SPhos
hierarchical_section_title: Dialkylbiaryl phosphine ligands / SPhos
context_page_description: In organic and organometallic chemistry, dialkylbiaryl phosphine ligands are phosphorus-containing supporting ligands that are used to modulate the chemical reactivity of palladium and other transition metal based catalysts. They were first described by Stephen L. Buchwald in 1998 for applications in palladium-catalyzed coupling reactions to form carbon-nitrogen and carbon-carbon bonds. Before their development, use of first- or second-generation phosphine ligands for palladium-catalyzed C-N bond-forming cross-coupling necessitated harsh conditions, and the scope of the transformation was severely limited. The Suzuki-Miyaura and Negishi cross-coupling reactions were typically performed with Pd(PPh₃)₄ as catalyst and were mostly limited to aryl bromides and iodides at elevated temperatures, while the widely available aryl chlorides were unreactive. The development of new classes of ligands was needed to address these limitations.
context_section_description: SPhos was first reported in 2004 as an extremely competent ligand in catalyzing Suzuki-Miyaura coupling reactions This ligand enables the cross-coupling of heteroaryl, electron-rich and electron-poor aryl, and vinylboronic acids with a variety of aryl and heteroaryl halides under mild reaction conditions.  SPhos has also been used in the Pd-catalyzed borylation of aryl and heteroaryl chlorides.
  
  3-Sulfonate variants of this ligand (sSPhos) have been shown to catalyze Suzuki-Miyaura couplings in aqueous media. One example of the application of SPhos to academia was its use in the 8 step total synthesis of (±)-geigerin.
caption: SPhos