Development of New and General Methods for Phosphine Synthesis. Seth B. Herzon, PhD, Department of Chemistry, Yale University, New Haven, CT We have developed a new and general method for the one-step synthesis of secondary phosphine oxides from simple carbonyl compounds and primary phosphines.
O R′ PH2 R
H
TFA 80 °C, 12–24 h
R, R′ = alkyl or aryl
R
P
O H
R′
23 examples 47–97%
We have developed a highly active catalyst system for the P-arylation of secondary phosphine oxides to form tertiary phosphine oxides.
R1 R2
P
O
Pd2dba3 (0.5 mol%) Xantphos (1 mol%) Ar–I
H
1 equiv
NEt3, 1,4-dioxane, 2 h, 24 oC 1.01 equiv
R1 R2
P
O Ar
(2)
60–95%
Because tertiary phosphine oxides can be reduced with retention or inversion of stereochemistry, we believe this method may constitute a general route to P-chiral tertiary phosphines.
