es 4a-h and 5e. The influence of the pentacoordinated phosphorus atom on the stereoselectivity of the Pudovik reaction might be attributed to the involvement of the rigid spirophosphoranide (PV) intermediate in the addition reaction. Selective and one-pot hydrolysis of these P-C bond spirophosphoranes readily proceeds either at room temperature in the presence of moist solvents to give the corresponding