Sterically protected organophosphorus compounds in low co-ordination states

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

“…Multiple bonds of heavier main group elements are important chemical species in main group chemistry and we have studied chemistry of low-coordinated phosphorus compounds [4] to find out various reactions and molecular structures [5][6][7]. In the course of our research on such lowcoordinated phosphorus compounds, we have found a useful synthetic method for 2,4-bis(2,4,6-tri-t-butylphenyl)-1,3-diphosphacyclobutane-2,4-diyls of biradical type (3) by use of a kinetically stabilized phosphaalkyne [Mes * C"P: 4] (Mes * = 2,4,6-tri-t-butylphenyl) [8][9][10].…”

Isolation of a Kinetically Stabilized 1,3,6-Triphosphafulvene

“…After purification (silicapacked column chromatography), 3 was obtained as a deep red solid together with trace amounts of 2-(2,4,6-tri-tertbutylphenyl)-1-(2,4,6-tri-tert-butylphenylphosphanyl)acetylene (6), 1-(2,4,6-tri-tert-butylphenyl)-1-phosphaacetylene (7), [5±7, 9] and 6,8-di-tert-butyl-4,4-dimethyl-1-phospha-3,4-dihydronaphthalene (8). [5,6,10] The 31 P NMR spectrum of 3 shows an ABX system. The signal of the exocyclic phosphorus atom P X (d P X 313.8) is positioned downfield compared to ring atoms P A and P B but similar to that found for 9 (d 321.5), [11] due to the electron-withdrawing effects of the 1,3-diphosphacyclopentadiene moiety.…”

1,3-Diphosphapropenes for novel chemistry of metal complexes

“…Novel 2-methyl-1,3-diphosphapropenes (2,4) were prepared and found to function as a monodentate and/or a chelating ligand of several transition-metal complexes. The dichloropalladium(II) complexes 12 and 14 displayed catalytic activities for the Sonogashira and Suzuki cross-coupling, although the activity was not as high as well-defined ligands with high activity.…”

“…Chemistry of low-coordinated phosphorus compounds has greatly developed in the past decades [1] and we have reported a number of phosphaethenes kinetically stabilized by bulky 2,4,6-tri-t-butylphenyl (hereafter abbreviated to Mes*) groups [2]. Previously we reported the preparation of 2-chloro-1,3-diphosphapropenes 1, which were used as ligands for transitionmetal complexes [3].…”