Synthesis and novel mass spectral rearrangements of 10-phenylphenoxaphosphine and some of its derivatives

Abstract

The successive treatment of phenyl ether with n-butyl-lithium and phenylphosphonous dichloride afforded virtually, in a one-step process, the title compound. The mass spectrum of the cyclic phosphine (Ia) was characterized by the loss of phenyl followed by a one-step elimination of both heteroatoms. Anchimeric assistance of the oxygen in the phenyl expulsion was supported by energetic considerations and by the observed one-step elimination of C₆H₅O· from the molecular ion of (Ia). A similar rearrangement was exhibited by bis-(o-methoxyphenyl)-phenylphosphine (IV), leading also to a rearranged carbon skeleton. The phosphine oxide (IIa) and sulphide (IIIa) exhibited rearrangements leading to the expulsion of C₆H₅O· and C₆H₅S· from the corresponding molecular ions.