title: P-C bond activation chemistry: evidence for 1,1-carboboration reactions proceeding with phosphorus-carbon bond cleavage.
abstract: A series of diarylphosphinyl-substituted acetylenes of the type (aryl)(2)P-C≡C-R (aryl = phenyl or mesityl, R = Ph or n-propyl) react with the strongly Lewis acid reagent B(C(6)F(5))(3) in toluene at elevated temperatures (70-105 °C) to give the 1,1-carboboration products 4. Treatment of bis(diphenylphosphinyl)acetylene with B(C(6)F(5))(3) under analogous conditions proceeded with phosphinyl migration to yield the 1,1-carboboration product 4d, bearing a geminal pair of Ph(2)P substituents at one former acetylene carbon atom and a C(6)F(5) substituent and the remaining -B(C(6)F(5))(2) group at the other. Prolonged thermolysis of 4d resulted in an intramolecular aromatic substitution reaction by means of Ph(2)P attack on the adjacent C(6)F(5) ring to yield the zwitterionic phospha-indene derivative 7. The compounds 4a, 4c, 4d, and 7 were characterized by X-ray diffraction.
authors.affiliation: Organisch-Chemisches Institut der Universität Münster, Corrensstrasse 40, 48149 Münster, Germany.
authors.forename: Olga
authors.initials: O
authors.lastname: Ekkert
authors.forename: Gerald
authors.initials: G
authors.lastname: Kehr
authors.forename: Roland
authors.initials: R
authors.lastname: Fröhlich
authors.forename: Gerhard
authors.initials: G
authors.lastname: Erker
mesh_terms: D000114:Acetylene / Q000737:chemistry; D001896:Boron Compounds / Q000138:chemical synthesis / Q000737:chemistry; D002244:Carbon / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D015394:Molecular Structure; D009943:Organophosphorus Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010758:Phosphorus / Q000737:chemistry*
chemical_list: D001896:Boron Compounds; D009943:Organophosphorus Compounds; D010758:Phosphorus; D002244:Carbon; D000114:Acetylene