Cycloadditions of 1H-1,3-Benzazaphospholes with o-Chloranil

Heinicke, Joachim W.; Gupta, Nidhi; Mayer, Peter und Karaghiosoff, Konstantin (2020): Cycloadditions of 1H-1,3-Benzazaphospholes with o-Chloranil. In: Zeitschrift für Anorganische und Allgemeine Chemie, Bd. 646, Nr. 13: S. 959-963

Abstract

NH-Functional 1H-1,3-benzazaphospholes 1a-1c and o-chloranil (tetrachloro-o-benzoquinone - TCBQ) undergo rapid [1+4]-cycloaddition in a 1:2 molar ratio to give 2a-2c as high-melting zwitterionic sigma(6)lambda(5)-phosphorus compounds. In the case of 2a the yield is high (rel. to TCBQ) even if the reactants were used in a 1:0.5 molar ratio. For the 2-tert-butyl-substituted compounds 2b and 2c the yields were significantly lower, in part by unidentified byproducts. Addition of excess TCBQ to crude 2c containing unconverted 1c did not increase but strongly decrease the amount of 2c. Crystallization and XRD analysis led to detection of a minor side or consecutive product 3c, formally corresponding to P=C bond cleavage and [1+4] cycloaddition of three equivalents TCBQ, two at the phosphinidene and one at the arylaminocarbene end. NMR spectroscopic data of 2a-2c including conclusive C-13 data for 2a give evidence of the structures of the new compounds.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Chemie und Pharmazie > Department Chemie
• Themengebiete: 500 Naturwissenschaften und Mathematik > 540 Chemie
• ISSN: 0044-2313
• Sprache: Englisch