Reactions of diphenylnitrilimine with phosphites and diazaphospholenes

Abstract

Reaction of diphenylnitrilimine (6) with phosphites (7) leads to the formation of α-phenylhydrazonophosphonates (9), whose configurational assignment about the CN bond has been determined.

αβ-Bis(phenylhydrazono)phosphine oxide (10I)[or (10II)] is obtained by the reaction of (6) with diazaphospholen cis-(8)[or trans-(8)], a mixture of (10I and III)[or (10II and IV)] being formed only after work-up. Configurational assignments about the two CN bond have been determined and the relative configuration of the two chiral centres in (10I–IV) has been tentatively assigned. The stereospecificity of this reaction is explained in terms of spirocyclic pentaco-ordinate phosphorus intermediates whose formation may be favoured by ligand subset symmetry.