This result, together with the above investigations of the mechanism of our photoredox-driven radical group transfer reaction, strongly suggests that the silicon atom plays a crucial role in the ring-opening process. Firstly, as no ring opening is observed when using an all-carbon framework (Scheme 2a), the β-silyl radical 14 appears to be readily oxidized to carbocation 15 whereas the carbon analogue is not. This is presumably a consequence of the additional stabilization afforded by the β-silicon effect. Secondly, ring-opening of the βsilyl carbocation 15 is facilitated by formation of the thermodynamically more stable silylium ion 16. Overall, these factors divert the radical reaction of vinyl silanes towards a direct group transfer process under photoredox catalysis.