Nonepimerizing Alkylation of H–P Species to Stereospecifically Generate <i>P</i>-Stereogenic Phosphine Oxides: A Shortcut to Bidentate Tertiary Phosphine Ligands

Abstract

The secondary R_P-(-)-menthyl alkylphosphine oxide was confirmed as configurationally stable toward base and was used in base-promoted alkylation, stereospecifically affording P-retained bis or functional tertiary phosphine oxides in excellent yields. The alkylated products were deoxygenated using oxalyl chloride followed by ZnCl₂-NaBH₄ to form P-inversed bidentate phosphine boranes in high stereoselectivities.