The use of t-BuOK in DMSO allows a smooth addition of Ph 2 PH, Cy 2 PH and Ph 2 P(O)H to various functionalized alkenes leading to polyfunctional phosphines in good yields. This method has been used to prepare precursors for P,P- and P,N-ligands. ... Herein, we wish to report that catalytic amounts of t-BuOK (20 mol%) in DMSO allow the hydrophosphination of functionalized alkenes of type 1 using either diphenylphosphine (2a) or an aliphatic dialkylphosphine ...