Modular Synthesis of Benzo[<i>b</i>]phosphole Derivatives via BuLi-Mediated Cyclization of (<i>o</i>-Alkynylphenyl)phosphine

Abstract

Treatment of an (o-alkynylphenyl)phosphine with a stoichiometric amount of BuLi effects a cyclization reaction to produce a 3-lithiobenzo[b]phosphole, which affords a variety of 3-substituted benzophospholes upon reaction with electrophiles. An example is given for the synthesis of a bis-benzo[b]phosphole, which can be further converted to the corresponding benzo[b]phosphole oxide possessing high electron affinity.