Intramolecular dearomative 1,4-addition of silyl and germyl radicals to a phenyl moiety

Herein, we present that the radicals [Ph$_3$PC(Me)EMes$_2$]˙ (2$^{Si}$ and 2$^{Ge}$) can be generated from the α-silylated and α-germylated phosphorus ylides Ph$_3$PC(Me)E(Cl)Mes$_2$ (1$^{Si}$ and 1$^{Ge}$) through one-electron reduction with Jones’ dimer ($^{Mes}$NacNacMg)$_2$ in benzene. Although isolation of the free radicals was not possible, the products of the intramolecular addition of the radicals to a phenyl substituent of the phosphorus moiety, followed by subsequent reaction with 2$^{Si}$ or 2$^{Ge}$ to the isolated species 3$^{Si}$ and 3$^{Ge}$, respectively, were observed. This transformation witnesses a dearomative 1,4-addition of tetryl radical species to the phenyl scaffold in a stereoselective anti-fashion.