Transition Metal-Free Synthesis of -Aminophosphine Oxides through C(sp³)-P Coupling of 2-Azaallyls

Radical reactions have been widely applied in C-P bond-forming strategies. Most of these strategies require initiators, transition metal catalysts, or organometallic reagents. Herein, a transition metal-free C(sp(3))-P bond formation to prepare alpha-aminophosphine oxides via deprotonative radical coupling processes of 2-azaallyls with chlorodiphenylphosphine oxides was presented. Deprotonation of N-benzyl imines may generate super-electron-donor (SED) 2-azaallyl anions that reduced chlorodiphenylphosphine oxides to phosphine oxide radicals. Single-electron transfer (SET) process transformed the 2-azaallyl anions into 2-azaallyl radicals, which may couple with phosphine oxide radicals to construct C-P bonds. The deprotonative radical coupling approach enables the synthesis of alpha-aminophosphine oxides bearing various functional groups under mild conditions and without precious transition metal catalysts or oxidants.