Kombinierte 3.3- und 3.4-Addition an ein 1.2.4.3λ3-Triazaphosphol zu Tricyclophosphoranen / Combined 3,3- and 3,4-Addition to a 1,2,4,3λ3-Triazaphosphole Yielding Tricyclic Phosphoranes

Abstract

2-Methyl-5-phenyl-2H-1,2,4,3λ3-triazaphosphole, which does not lend itself to oxidative additions alone, reacts smoothly with o-heterodienyl-phenols yielding tricyclic phosphoranes. The reaction involves an initial addition of the phenolic end to the P=N bond and a subsequent fast intramolecular addition of the heterodiene moiety to the phosphorus. The structure of the resulting phosphoranes is proposed to have all three fivemembered rings attached to the central trigonal bipyramidal phosphorus by one axial and one equatorial bond with the bond in common to the two condensed rings in axial position. NMR data back this proposal.