Reactions of 1,3,6-Triphosphafulvene and the Related Compounds Affording Unique Phosphorus Compounds

Abstract

The 1,3,6-Triphosphafulvene showed regioselective reactivity toward alkyllithiums at the external phosphorus atom to afford the corresponding phosphinodiphospholide anions. The diphospholide anions were allowed to react with alkyl halides to yield the corresponding phosphinodiphospholes. On the other hand, the generated phosphinodiphospholide anions were allowed to react with acetic acid to afford the diphosphacyclopentadienylidenephosphoranes, which are phosphorus ylides bearing a P-H bond. Alternatively, reaction of the 1,3,6-triphosphafulvene with tetrafluoroboric acid afforded the phosphorus ylide bearing a P-H bond. The structure of the phosphorus ylide was analyzed by crystallography and was discussed. Additionally, we studied reactivity of 6-phosphafulvene to compare with the property of 1,3,6-triphosphfulvene. Furthermore, a 3,4-dihydro-1,3,4-triphosphacyclopenta[a]indene was isolated in the reaction to obtain the 1,3,6-triphosphafulvene.