Details

Autor(en) / Beteiligte

• BERNHARDT, FRANK CHRISTIAN

Titel

THE STUDY OF ISOPHOSPHINDOLINE DERIVATIVES: APPROACHES TO ISOPHOSPHINDOLES

Ort / Verlag

ProQuest Dissertations Publishing

Erscheinungsjahr

1985

Link zum Volltext

Quelle

ProQuest Dissertations & Theses A&I

Beschreibungen/Notizen

• The synthesis and study of benzo-7-phosphanorbornene phosphines, a new class of phosphorus heterocycles, were accomplished. The ('31)P NMR spectra of these phosphines revealed that the ('31)P nuclei in these systems were extremely deshielded. The phosphine with a P-tert-butyl substituent gave the most downfield value ((delta) +152.5) ever recorded for a tertiary phosphine. These systems were prepared from the Diels-Alder adducts of isophosphindole oxides with norbornadiene. Reduction with trichlorosilane-pyridine gave the phosphines. The structural representations of these compounds can be found on pages 37 and 43 of the dissertation. Both the phosphines and phosphine oxides were characterized by ('31)P and ('13)C NMR. The effect of lone pair orientation in the phosphines on ('2)J(,PC) and ('3)J(,PC) was used to determine stereochemical features in these systems. The 2-phenylisophosphindole 2-oxide dimer reported by Chan and Nwe was characterized by ('31)P and ('13)C NMR and the proposed structure was further confirmed by the data in these spectra. The phosphine of the dimer was seen as a useful precursor to the isophosphindole system. However, the reaction of trichlorosilane-pyridine with this dimer gave an abnormal reaction product, 2-phenyl-1-(2-phenylisophosphindolinyl)isophosphindoline 2-oxide. The previous benzo-7-phosphanorbornene systems were also of interest as precursors of the previously unknown isophosphindole system. The mass spectrum of the P-tert-butyl derivative indeed contained a signal at m/e 133, which was assigned to the isophosphindole skeleton. However, pyrolysis of these systems under flash vacuum pyrolysis conditions at various temperatures gave only naphthalene and diphenylphosphine. The latter product was formed by an unknown route from the P-phenyl derivative. Another approach to the isophosphindole system included attempted dehydrohalogenations of 2-chloroisophosphindoline. The products of these reactions were proposed to be the P-P bonded bis-isophosphindoline and its various oxidation products. The methiodide salt of 2-phenylisophosphindoline was used in an approach analogous to Wittig's synthesis of 2-methylisoindole. However, the product of this reaction was the ring-opened phosphine oxide, which is illustrated on page 90 of the dissertation. Mathey's method of synthesizing phospholes by the dehydrohalogenation of McCormack cycloadducts was applied to the bromine salt of 2-phenylisophosphindoline. The reaction of this salt with triethylamine or 2-picoline gave only a bromide salt-amine complex and not the desired isophosphindole.