Phosphorus Heterocycles: From Laboratory Curiosities to Ligands in Highly Efficient Catalysts

Abstract

Phosphabenzenes and phosphaferrocenes were among the first compounds with P−C multiple bonds. For nearly 30 years the chemistry of these molecules was essentially a domain left to basic researchers. Recently, however, it was reported that transition metal complexes with phosphabenzene and phosphaferrocene ligands exhibit remarkable potential as catalysts. Catalysts based on rhodium (I) and various phosphabenzenes appear to be superior to classical systems in the hydroformylation of terminal and internal alkenes. In addition planar‐chiral phosphaferrocene species display an excellent performance as directing ligands in a series of enantioselective asymmetric syntheses.

Synthesis and properties of air-stable 1,3-diphosphacyclobutane-2,4-diyls and the related compounds

“…The lower reduction potentials of 3f-h relative to that of 3a might indicate differences between unsymmetrical and symmetrical 1,3-diphosphacyclobutane-2,4-diyls. Indeed, the unsymmetrical 1,3-diphosphacyclobutane-2,4-diyl 3a and 3b bear considerably shorter P-C sp2 bonds (vide infra) [8,10], which might increase electron-accepting ability as observed in phosphaalkenes [4,15]. (Table 3).…”

Accessing Alkyl- and Alkenylcyclopentanes from Cr-Catalyzed Ethylene Oligomerization Using 2-Phosphinophosphinine Ligands

“…27 Dppe (F, R = H), and related ligands with hydrocarbyl backbones containing unsaturation (G, H) either with or without backbone substitution, also work well in selective ethylene tetramerization catalysis. 27,29 The use of donor-functionalised phosphinines in catalysis is a growing field, [30][31][32][33][34] and incorporation of the ligand backbone and one phosphorus donor in an unsaturated heterocycle, in the form of an aromatic phosphinine, 35 would protect the ligand backbone from deprotonation and give unsymmetrical 2-phosphinophosphinine ligands with potentially very different properties. 32,[35][36] Ligand 1 has recently been used in the Ru catalysed transfer hydrogenation of acetophenones at room temperature as well as the catalytic 'hydrogen borrowing' upgrading of EtOH/MeOH to i BuOH.…”

Theoretical Study of the Tautomerism, Structures, and Vibrational Frequencies of the Phosphaalkenes XP═C(CH3)2(X = H, F, Cl, Br, OH, ArF(ArF= 2,6-(CF3)2C6H3))

“…[10][11][12][13][14] As the field has advanced, applications of phosphaalkenes are also being pursued. These include their use as ligands in transition-metal-catalyzed organic reactions 5,[15][16][17][18][19][20] and as sources for new inorganic polymers. [21][22][23] One strategy in the development of new inorganic polymers is to use addition polymerization of PdC bonds, yielding new poly(methylenephosphine)s. One example was reported for MesPdCPh 2 by Tsang et al 22 This group wished to extend this work to a wider range of substituents.…”