One-Pot Process That Efficiently Generates Single Stereoisomers of 1,3-Bisphosphinylpropanes Having Five Chiral Centers

P,C-Stereogenic 1,3-bisphosphinylpropanes 3 that have up to five stereogenic centers could be obtained stereoselectively in high yields by a one-step reaction of (RP)-menthylphenylphosphine oxide 1 with α,β-unsaturated aldehydes 2 catalyzed by KOH at room temperature. A mechanism was proposed as to involve a stereoselective intermolecular 1,3′-phosphorus migration from the 1,2-adduct of 1 with 2 to another 2 generating a 1,4-adduct that subsequently reacts with 1 to produce 3.