Abstract: The first segment of this presentation will detail our development of a methodology to control π-facial selectivity in intramolecular Diels–Alder cyclizations using a silacycle directing group. A panel of substrates is synthesized and tested, providing insight into the capabilities and, more importantly, the limits of the methodology. Deeper mechanistic insight is gained through a deuterium-labelling study, which suggests the role of [1,5] hydride shifts in the formation of the reactive diene.