Transition‐Metal‐Free Ring‐Opening Silylation of Indoles and Benzofurans with (Diphenyl‐tert‐butylsilyl)lithium

A practical method is presented for ring opening various indoles and benzofurans with concomitant stereoselective silylation using readily generated (diphenyl‐tert‐butylsilyl)lithium to afford ortho‐β‐silylvinylanilines or ‐phenols. Dearomatization of the heteroarene core proceeds in the absence of any transition‐metal catalyst through addition of a silyl anion and a subsequent stereoselective β‐elimination. DFT calculations provide insight into the mechanism. Functionalizing C−X bond cleavage of heteroarenes is rare and generally requires transition‐metal catalysts. Open for business: Ring‐opening silylation of various indoles and benzofurans using diphenyl‐tert‐butylsilyllithium affords ortho‐β‐silylvinyl anilines or phenols. Dearomatization of the heteroarene core proceeds in the absence of any transition‐metal catalyst through addition of a silyl anion and a subsequent stereoselective β‐elimination.