Methylpropylphenyl phosphine oxide

Optically active (+)-(R) methylpropylphenyl phosphine oxide 39 was reduced using the Homer method, and then the produced phosphine was oxidized by adding 1.2 molar equivalent of BTSP at room temperature. (—)-(S) methylpropylphenyl phosphine oxide 40 was obtained with 95% stereospecificity. Since the reduction step is known to proceed with inversion of the configuration at the phosphorus center , oxidation occurs with retention (equation 63). 

---