title: Fused tricyclic phosphiranes--analysis of phosphorus chemical shieldings.
abstract: 1,2-Addition of transient W(CO)(5)-complexed phosphinidenes exo to hexamethyl Dewar benzene affords the novel 3-phosphatricyclo[3.2.0.0(2,4)]hept-6-ene complexes. The fused tricyclic phosphiranes are obtained as both the Z and the thermally less stable E isomers, the (31)P NMR chemical shifts of which differ by about 60 ppm. A computational investigation shows that the phosphorus pyramidalization and the presence of the gamma double bond are responsible for this effect. The semiquantitative results contribute to a more systematic understanding of the structural influences on (31)P chemical shieldings. The congested double bond of the Z isomer can be epoxidized with m-chloroperbenzoic acid (MCPBA) to afford a fused tetracyclic P,O bis-adduct.
authors.affiliation: Department of Organic Chemistry, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1083, Amsterdam, The Netherlands.
authors.forename: Erik P A
authors.initials: EP
authors.lastname: Couzijn
authors.forename: Andreas W
authors.initials: AW
authors.lastname: Ehlers
authors.forename: J Chris
authors.initials: JC
authors.lastname: Slootweg
authors.forename: Marius
authors.initials: M
authors.lastname: Schakel
authors.forename: Steffen
authors.initials: S
authors.lastname: Krill
authors.forename: Martin
authors.initials: M
authors.lastname: Lutz
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Spek
authors.forename: Koop
authors.initials: K
authors.lastname: Lammertsma
mesh_terms: D000465:Algorithms; D002723:Chlorobenzoates / Q000737:chemistry; D004852:Epoxy Compounds / Q000737:chemistry; D006575:Heterocyclic Compounds, 3-Ring / Q000737:chemistry*; D007536:Isomerism; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009943:Organophosphorus Compounds / Q000737:chemistry*; D010758:Phosphorus / Q000737:chemistry*
chemical_list: D002723:Chlorobenzoates; D004852:Epoxy Compounds; D006575:Heterocyclic Compounds, 3-Ring; D008024:Ligands; D009943:Organophosphorus Compounds; D010758:Phosphorus; C000433:3-chloroperbenzoic acid