Photocatalytic E→Z Contra‐Thermodynamic Isomerization of Vinyl Silanes with Lewis Base

Herein, we disclosed the contra‐thermodynamic E→Z isomerization of alkenyl silanes, according to the in situ formation of a chromophoric species, in the presence of rac‐BINAP as the catalyst. The reaction carried out in DMSO or CH(3)CN under irradiation at 405 nm allowed the interconversion of the E‐isomers into the Z‐congeners in good to excellent yields and outstanding Z/E selectivities, on 18 examples. Finally, the mechanism of this E→Z isomerization was studied to get insight into the reaction mechanism.