Synthesis of Disilanes, Dihydrosiloles, and 1,4‐Disilacyclohexa‐2,5‐dienes by Transition‐Metal‐Free Transfer of Diphenylsilylene and Dimethylsilylene from Silylboronic Esters

Abstract We found that the transfer of diphenylsilylene (Ph 2 Si:) from Ph 2 (Et 2 N)Si−B(pin) ( 1 a ) takes place in toluene or p ‐xylene at 110–135 °C under transition‐metal‐free conditions. The reaction of alkoxysilanes with 1 a affords alkoxydisilanes through the insertion of diphenylsilylene into the Si−O bond. Dihydrosiloles and a 1,4‐disilacyclohexa‐2,5‐diene are synthesized by the reaction of 1 a with 1,3‐dienes and an alkyne, respectively, through cycloaddition of the carbon‐carbon unsaturated bonds with diphenylsilylene. Me 2 (Et 2 N)Si−B(pin) ( 10 ) is applicable to the transition‐metal‐free transfer of dimethylsilylene (Me 2 Si:).