A catalytic cycle consistent with all available mechanistic data is depicted in Fig. . This cycle features (i) a protonation equilibrium that favors the phosphonium chloride 10a, (ii) binding of 10a to monomeric catalyst 1g forming the resting state, and (iii) turnover-limiting and enantiodetermining dealkylation to form product 3a and benzyl chloride, which dissociate from the catalyst to turn over the catalytic cycle.