To explore this hypothesis, we selected the Michaelis-Arbuzov reaction as a prototypical transformation proceeding through a phosphonium intermediate. Specifically, we directed our attention towards the protio-Michaelis-Arbuzov variant that yields enantioenriched Hphosphinates, P-stereogenic building blocks with broad synthetic utility but that are currently only accessible by stoichiometric approaches (Fig. , right) .