Modular Synthesis of Functionalized Benzosiloles by Tin-Mediated Cyclization of (o-Alkynylphenyl)silane

Trimethylstannyllithium promotes cyclization of (o-alkynylphenyl)silane into a 3-stannylbenzosilole, via addition to the triple bond followed by intramolecular cyclization in a cascade fashion. This intermediate can be functionalized with either electrophiles or nucleophiles to allow modular synthesis of 2,3-disubstituted benzosiloles. One of these compounds, a phenylene-bis(benzosilole) compound, shows electron drift mobility as high as 6 x 10-4 cm2/Vs in an amorphous film, making this class of compounds promising electronic materials for organic light emitting devices and organic photovoltaic cells.