A newsynthesis of unsymmetricalphosphinicacids R′P(O)OHR″ has been evaluated. The first P–C bond was formed by base-promoted H-phosphinate alkylation of a protected H-phosphinate, which is easier and safer to handle. A one-pot methodology was developed for the second P–C bond formation reaction that involves the sila-Arbuzov reaction. This methodology was then extended to the synthesis of a dialkylphosphinic