78. Zimmerman,
A. N.; Xu, R. S.;
Reynolds, S. C.; Shipp, C.
A.; Marshall, D. J.; Wang,
G.; Blank, N. F.; Gibbons,
S. K.; Hughes, R. P.;
Glueck, D. S.; Balaich, G.
J.; Rheingold, A. L.
Diastereoselective
Synthesis of P-Stereogenic
Secondary Phosphine Oxides
(SPOs) Bearing a Chiral
Substituent by Ring
Opening of (+)-Limonene
Oxide with Primary
Phosphido Nucleophiles. J.
Org. Chem.
2020, 85, 14516–14526.
Abstract
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.
