Diastereoselective Synthesis of P‑Stereogenic Secondary Phosphine Oxides (SPOs) Bearing a Chiral Substituent by Ring Opening of (+)-Limonene Oxide with Primary Phosphido Nucleophiles

Kinetic
separation of the commercially available cis/trans-(+)-limonene oxide mixture by ring opening
with primary phosphido nucleophiles LiPHR (R = ferrocenyl, Ph, Cy, t-Bu, Mes* (Mes* = 2,4,6-(t-Bu)3C6H2)), followed by treatment with aqueous
NH4Cl and H2O2, gave unreacted cis-(+)-limonene oxide and diastereoenriched mixtures of
the secondary phosphine oxides (SPOs) PHR­(trans-(+)-Lim–OH)­(O),
which could be separated by chromatography and/or recrystallization.
This one-pot synthesis uses a cheap chiral material and commercially
available primary phosphines to control the configuration of the new
P-stereogenic SPOs, which are potentially useful as ligands for metal
complexes in asymmetric catalysis.